bluuebunny/crossref_metadata_2025 huggingface dataset:
Acute Diaphragm Stimulation Elicits Phrenic Afferent Induced Neuromuscular Plasticity
Authors: Popp Nicole M. , Holmes Taylor C. , Streeter Kristi A.
Published: May 2022

Activation of phrenic afferents increases phrenic motor output and induces short‐term plasticity. Here we tested the hypothesis that activation of phrenic afferents via acute diaphragm stimulation induces neuromuscular plasticity within the phrenic motor system. Bilateral EMG activity was recorded from the mid‐costal diaphragm of anesthetized and spontaneously breathing rats. Inspiratory‐triggered stimulation was delivered to the left diaphragm for 30 minutes at twitch threshold (n=7; 0.6 ± 0 mA) or 1.5X twitch threshold (n=7; 1.0 ± 0.12 mA), and output was recorded for 60 minutes post‐stimulation. Arterial blood gas samples revealed that PaCO2 was no different than baseline during or after stimulation (P=0.2204) or across experimental groups (P=0.3534). Diaphragm amplitude ipsilateral and contralateral to stimulation was increased 60 minutes following threshold (P=0.0021 and P=0.0096) and 1.5X threshold (P=0.0003 and P=0.0448) stimulation compared to time controls (n=7). Separate groups of rats received 1.5X threshold stimulation and either a C3‐C6 laminectomy (n=6; 0.8 ± 0.06mA) or a left C3‐C6 dorsal rhizotomy (n=6; 0.7 ± 0.10mA) to prevent afferent input from reaching the spinal cord. Laminectomy controls continued to express neuromuscular plasticity ipsilateral (P=0.0017) and contralateral (P=0.0076) to stimulation compared to time controls. By contrast, following unilateral dorsal rhizotomy, ipsilateral and contralateral diaphragm amplitude 60 minutes post‐stimulation was lower than laminectomy controls (P=0.0107 and P=0.0115) and no different than time controls (P=0.5692 and P=0.4784), suggesting neuromuscular plasticity was not induced. Our results indicate that acute diaphragm stimulation induces a novel form of neuromuscular plasticity which requires activation of phrenic afferents. We hypothesize that phrenic afferent induced neuromuscular plasticity may be valuable as a therapeutic strategy following spinal cord injury.
Optimizing the cODC degron for Protein Control in Nematode Worms
Authors: Valero‐Davlia Felix , Johnson Grant M. , Huynh Nhan , Sorensen Erika B. , Novak Walter R.
Published: May 2022

Caenorhabditis elegans, a nematode worm, is a model multicellular organism for the study of development and disease. Current methods of controlling essential and pleiotropic gene product levels in C. elegans suffer from limitations, including incomplete penetrance, false negatives, and the inability to differentially control multiple genes with the same system simultaneously. Genetic control methods such as loss‐of‐function alleles and CRISPR‐Cas9 targeted genes have proved successful at deducing the relationship between gene function and phenotype; but they lack the ability to investigate genes essential for viability, fertility, and pleiotropic genes that have dissimilar roles in different tissues during the nematode’s lifespan. RNAi is an effective method for studying gene function in C. elegans, it is easy to deliver, can target virtually any sequence, and can be administered at any time during development. However, RNAi suffers from several limitations including: a significant portion of genes cannot be adequately silenced, RNAi cannot enter equally into all tissues, there is a risk of off‐target effects, and the observation that RNAi phenotypes may be delayed if existing proteins persist for long periods of time. Protein degradation methods can overcome many limitations of the genetic methods by genetic fusion of the gene of interest to an inducible protein degradation domain. Some protein control methods lack the ability to target control of protein degradation to specific tissues, while all current methods are limited by the use of a single input signal to control degradation. The overarching goal of this study is to develop a system for complex control of protein function in nematodes using the Latching Orthogonal Cage/Key pRoteins (LOCKR) system, a de novo‐designed protein Switch comprised of a Cage and a Latch that is capable of caging any linear protein sequence. To conditionally control protein levels in nematodes, we will fuse target genes to LOCKR with a cODC degron sequence encoded in the Latch. The interaction of the Cage with the Latch blocks the accessibility of the degron. Introducing a peptide Key releases the Latch, resulting in exposure of the degron sequence and degradation of fused proteins. Here we describe the development of a bacterially‐expressed LOCKR system suitable for in vitro degron optimization. The mEGFP‐degronLOCKR fusion expresses in bacteria and can be purified using immobilized metal affinity chromatography. We hypothesize that when Switch is activated by the Key and the degron is exposed, the mEGFP‐degronLOCKR construct will be degraded in C. elegans lysate. We further predict that various mutations in the degron will affect the rate of target protein degradation. This study will allow more detailed and complex studies of development and disease in C. elegans and may be applicable to other multicellular organisms.
Unilateral Vagotomy Blunts Cardiorespiratory Responses to Vagal Afferent Stimulation and Nucleus Tractus Solitarii (NTS) Glutamate Microinjection
Authors: Hofmann Gabrielle C. , Kline David D. , Hasser Eileen M.
Published: May 2022

The nTS of the brainstem is the initial integration site of sensory information from the cardiorespiratory system, including afferents from the vagus nerve carrying input from the heart and lungs. The nTS is an important site of neuroplasticity, which depends on factors including neuronal and astrocytic activity, with the latter regulating glutamate (Glu) signaling. We have shown that unilateral transection of the vagus nerve to decrease afferent input results in morphologic changes in nTS glia. Vagal nerve transection also decreases nTS synaptic transmission studied in vitro. The influence of vagotomy on in vivo cardiorespiratory function via afferent‐driven Glu signaling is unknown. We hypothesized that chronic vagotomy blunts cardiorespiratory responses to vagal afferent stimulation via decreased Glu signaling. Male Sprague‐Dawley rats (6‐wk, N=19) were randomly assigned to vagotomy or sham groups. Right cervical vagus nerve transection caudal to the nodose ganglion or sham surgery was performed. One week after surgery, rats were anesthetized, ventilated, and instrumented to measure mean arterial pressure (MAP), heart rate (HR), splanchnic sympathetic and phrenic nerve activity (SSNA and PhrNA, respectively). Intact vagus nerves were transected acutely to prevent efferent stimulation. Left and right vagus nerves were stimulated (20 sec, 0.2mA, 2‐10Hz, 0.5ms pulse width) and responses recorded for 3 minutes. Chronic vagotomy had no effect on baseline cardiorespiratory parameters compared to shams. Vagal nerve stimulation on either side increased MAP, HR, and SSNA and decreased PhrNA in all groups. There were no consistent group differences in MAP, HR, and SSNA responses. However, chronic vagotomy blunted the stimulation‐induced decrease in PhrNA frequency and amplitude and decreased apnea duration on the ipsilateral side compared to contralateral stimulation and to shams. To evaluate the mechanism of altered respiratory responses, Glu was nanoinjected (30nL, 1‐10mM) into the left and right nTS of chronic vagotomy and sham rats. Glu decreased MAP, HR, SSNA, and PhrNA in all groups and on both sides. Chronic vagotomy had minimal effects on MAP and SSNA responses, but blunted the decrease in HR and PhrNA frequency and amplitude during ipsilateral Glu injection compared to contralateral. The blunted responses to vagal afferent stimulation and nTS glutamate suggest that chronic vagotomy alters Glu signaling in part via postsynaptic mechanisms. Additional experiments are needed to determine the mechanisms (including the role of astrocytes) of altered nTS Glu signaling to changes in afferent input in cardiorespiratory health and disease.
COVID‐19: Implications Regarding the Properties and Behaviors of the Coronavirus Disease
Authors: Chen Mark H. , Tulp Orien L. , Einstein George P.
Published: May 2022

The novel coronavirus SARS‐Cov‐2 or COVID‐19 became a global pandemic and currently few medically approved curative treatments exist. SARS‐Cov‐2 acts similarly to SARS‐CoV‐1 from where it may have evolved. The COVID‐19 virus can survive ~3 hours in air and < 72 hours on distinct surfaces. COVID‐19 mutates by introducing sequence errors in the host’s RNA genome or by modifying proteins and enzymes. Vaccination, including booster shots, social distancing and isolation are the most generally practiced guidelines in the global management of COVID‐19. Globally the most frequently utilized pharmacologic treatments include ivermectin, hydroxychloroquine, glucocorticoids, the anti‐viral agent remdesivir, monoclonal antibodies, and convalescent plasma in combination with an antimicrobial agent such as azithromycin to minimize secondary microbial infection and nutritional supplementation (vitamins C, D3, and zinc) to enhance cellular immune responses and are included in the routine protocols of some emergency rooms. COVID‐19 viral transmission occurs via respiratory microdroplets, by inhaling COVID‐19 laden airborne particles and contact with contaminated surfaces on which these droplets have been deposited. SARS‐CoV‐2 targets ACE2 receptors in the upper and lower respiratory tracts in addition to the heart, brain, and gastrointestinal tract, and may cause thromboses in the liver, heart, and kidney.

Significant risk factors for the severity of COVID‐19 infection include advanced age and pre‐existing comorbid conditions obesity, hypertension, cardiovascular disease, diabetes, and compromised immune status, which all correlate with greater mortality. Outcome‐effecting factors include viral load, viral mutations, and pre‐existing conditions. Since its origination, genomic studies of the virus have identified numerous variants which have become regionally prevalent in different countries. Infective factors, comorbidities and viral load strongly affect outcomes; patients infected with the greatest viral load showed a higher mortality. It is opined that the number of deaths attributed to COVID‐19 may be inaccurate due to errors in diagnosing and reporting, since other similar illnesses may exhibit similar symptoms.

Future research should focus on prevention practices, comorbidities, genetic prevalence, reliable systematic and consistency in country‐by‐country testing and reporting procedures, further scrutiny regarding the efficacy of current vaccines and protocols, and the pursuit for innovative therapies for Coronaviruses and variants including biophotonics and exploration of emerging bioenergetic, nutritional, pharmacological, immunotherapeutic and vaccination‐preventive applications for eradication of COVID‐19.

Refs: 1. Cheng, RZ. (2020a). Med Drug Disc, 5, 100028; 2. Shankar, AH, & Prasad, AS. (1998). ACJN, 68(2), 447S‐463S; 3. Petrilli, CM, Jones, SA, et al. (2020); medRxiv; 4.van Doremalen, N, Bushmaker, T et al. (2020). NEJM, 382(16), 1564‐1567
Synergistic Effects of Adavosertib, WEE‐1 Inhibitor in Combination with Cytarabine in the Jurkat Leukemia Cell Model
Authors: Rodríguez‐Vázquez Gabriel O. , Diaz‐Quiñones Adriana O. , Salgado Iris K. , Silva Ortiz Walter I. , Maldonado Héctor M.
Published: May 2022

Current treatment for leukemia focuses on DNA damaging treatments (DNAdt), including chemo (cytarabine, vincristine, doxorubicin, etc.) and/or radiotherapy. However, in both adult and pediatric patients with Acute Lymphoblastic Leukemia (ALL), value of these treatments are limited by development of chemoresistance. Recent studies evaluated inhibition of the G2‐M gatekeeper (Wee‐1 kinase) as a possible alternative treatment for other types of cancer, such as: breast, prostate, pancreatic, lung, leukemia, glioblastoma, among others. Adavosertib (AZD‐1775), a well‐documented Wee‐1 kinase inhibitor, has shown synergistic; chemo‐sensitization effects, and is currently undergoing clinical trials. Therefore, our working hypothesis is that: AZD‐1775 sensitizes Leukemia cell lines to DNA‐damaging drugs like cytarabine, resulting in a drug combination with significant synergistic effects. This study evaluates the cytotoxic and chemo‐sensitization effect of AZD‐1775 on an ALL T‐cell model (Jurkat). A broad range of drug combinations (high throughput 384 well plates format) in cell viability assays (96 hours; resazurin‐based) was used to determine cytotoxic effects of AZD‐1775 and cytarabine. Corresponding IC50 values were calculated using GraphPad Prism and the nature of the interactions (synergy, additivity, antagonism) determined with open access software CompuSyn, Combenefit, and SynergyFinder. The Combenefit freeware permitted fitting and analysis of the data to various synergy models (Loewe‐additivity, Bliss‐independence and Highest‐single Agent) while SynergyFinder allowed for an additional model (Zero Interaction Potency), and the classical model of CompuSyn allowed estimates of drug combination indexes (CI) and dose‐reduction indexes (DRI). The individual agents exhibited the following rank order of inhibitory potencies (IC50±SEM): cytarabine (160nM±6nM) ≥ AZD‐1775 (370nM±9nM). Drug combinations results demonstrate a strong and statistically significant synergistic effect with the highest synergistic interactions obtained with AZD‐1775 concentrations of 58nM to 270nM, and cytarabine concentrations of 8nM to 125nM. These synergistic interactions were observed independent on the model and software used for the analysis. Furthermore, the drug combination found to produce the highest synergistic effects in our resazurin‐based cytotoxic assay (AZD‐1775 = 97nM; Cytarabine = 63nM), was also used in a study using Jurkat, normal PBMCs, and activated T‐cells with cells analyzed for cell proliferation, viability and biochemical markers evaluated by Western Blot. At these low concentrations combination no synergistic effects were observed in normal PBMC cells; yet, our findings strongly demonstrate that AZD‐1775 can act as a chemosensitizer agent in ALL capable of potentiating the effect and susceptibility to cytarabine.
Photodynamic Activation of Cholecystokinin 1 Receptor Is Evolutionarily Conserved
Authors: Cui Zong Jie , Wang Jie
Published: May 2022

Cholecystokinin 1 receptor (CCK1R) is photodynamically activated permanently by singlet oxygen in rat pancreatic acini or in cell lines ectopically expressing human CCK1R, with light irradiation after exposure to photosensitizer sulphonated aluminium phthalocyanine (SALPC) or miniSOG. It is scientifically important to determine whether this property is evolutionarily conserved. Therefore photodynamic activation of CCK1R in pancreatic acini isolated from rat, mouse, Peking duck, and of CCK1R (or CCK1R‐like receptor) from human, rat, mouse, Peking duck, zebrafish, drosophila, C. elegans expressed in CHO‐K1 cells was examined, as monitored by Fura‐2 fluorescence calcium imaging. SALPC photodynamic action (SALPC 1 μM + LED 675 nm / 40 mW·cm‐2, 1.5 min) was found to trigger persistent calcium oscillations in pancreatic acinar cells isolated from rat, mouse, Peking duck, a hallmark of permanent photodynamic CCK1R activation, as well as in CHO‐K1 cells expressing CCK1R or CCK1R‐like receptor of human, rat, mouse, Peking duck, zebrafish, drosophila, C. elegans origin. Further, miniSOG photodynamic action (miniSOG fused to the C‐terminus of CCK1R + LED 450 nm / 85 mW·cm‐2, 1.5 min) elicited persistent calcium oscillations in CCK1R‐miniSOG‐CHO‐K1 cells, with CCK1R or CCK1R‐like receptor of human, rat, mouse, Peking duck, zebrafish, drosophila, and C. elegans origin. It is concluded therefore that photodynamic CCK1R activation is evolutionarily conserved from worm to human being. Although the structural basis for photodynamic CCK1R activation remains to be elucidated, it is noteworthy that certain critical singlet oxygen‐susceptible residues in CCK1R are conserved among these species.
Chronic Intermittent Hypoxia Impacts Bone Marrow Macrophages
Authors: Zhang Zishan , Berschel Mackenzie , Delloro Derick , Delzell Matthew , Jedlicka Charles , Lane Carter , Vasilyev Mikhail , Vasileva Anastasiia , Tomasson Michael H. , Bates Melissa L.
Published: May 2022

Sleep apnea is highly prevalent in patients with multiple myeloma, a rare and incurable cancer of malignant plasma cells, and is associated with poor outcomes. Chronic intermittent hypoxia (CIH), a feature of sleep apnea, facilitates myeloma development in mice. However, the mechanism by which CIH contributes to myeloma progression remains unknown. Our objective was to test the hypothesis that CIH provides a fertile environment for malignant cell engraftment via polarization of bone marrow macrophages. We exposed mice to chronic intermittent hypoxia (12 cycles/hr,10 hr/day) or 21% oxygen (control), harvested bone marrow, and assessed the impact of CIH on the percentage of bone marrow macrophages, B cells, plasma cells, T cells flow cytometry. Expression of Arg1, Mrc1, and Chi3l3 in bone marrow macrophages (CD11b+ F4/80+) of CIH‐exposed mice was quantified by qPCR. We evaluated the transcriptome alteration in bone marrow cells of mice exposed to CIH and normoxia by conducting bulk RNA sequencing and single‐cell RNA sequencing. Overall, CIH did not impact the number of macrophages in the bone marrow microenvironment but increased transcription of Arg1, Mrc1, and Chi3l3, transcripts associated with tumor associated‐macrophages, relative to the transcription of IL‐1β, TNF‐α, and iNOS, transcripts associated with anti‐tumorigenic macrophages. RNA sequencing of whole bone marrow supports the increased expression of macrophage markers consistent with tumor‐associated macrophages, and pathway analysis further highlights the role of macrophages. Single‐cell sequencing demonstrated that CIH‐induced genes co‐localize to a single cell population. In conclusion, we found that CIH exposure causes changes to myeloid cell populations in the bone marrow of mice and increases the transcription of genes relevant to myeloma tumor development in macrophages.
PCID2 assists in the nuclear export of nucleophosmin (NPM) in HeLa cells
Authors: Schwab Nevan , Resendes Karen
Published: May 2022

PCI‐domain containing protein 2 (PCID2) plays a key role in facilitating the nuclear export of various proteins. PCID2 further functions by localizing to the centrosome, where it likely helps to regulate the process of centrosome duplication. Nucleophosmin (NPM) is a nucleolar protein that undergoes Crm1‐dependent nuclear export and also associates with centrosomes to prevent premature cell division. Other proteins reliant on Crm1 for nuclear export, including BRCA1, further require the presence of PCID2 for efficient nuclear export and subsequent centrosomal localization. Here, we show that NPM is also reliant on PCID2 for its nuclear export through the use of siRNA knockdown on HeLa cells. Immunofluorescence revealed a 34% increase in nuclear fluorescence of NPM without PCID2, while centrosomal localization of NPM exhibited no direct impact due to removal of PCID2. These results identify a supporting role for PCID2 in the regulation of centrosome duplication through the facilitation of NPM nuclear export to the cytoplasm. Ongoing studies seek to identify NPM and PCID2 complexes via immunoprecipitation as well as exploring the possible effects of PCID2 knockdown on the structure or composition of the nucleolus and on NPM subnuclear localization. Our research has identified a role for PCID2 in the regulation of NPM nuclear export, providing potential insight into the development of tumorigenesis due to centrosome amplification and possible changes to nucleolar structure and composition.
Targeted Metabolomics Reveals Plasma Biomarkers and Metabolic Alterations of the Aging Process in Healthy Young and Older Adults
Authors: Patterson Jeffrey , Jasbi Paniz , Jin Yan , Nikolich‐Zugich Janko , Knox Kenneth , Weinstock George , Smith Patricia , Twigg Homer , Gu Haiwei
Published: May 2022

With the exponential rise in the older population for the coming years, many studies have aimed to further investigate potential solutions to the aging process. It has been well understood that age is the largest risk factor for chronic disease due to younger individuals possessing more prevalent and adaptive metabolic networks that result in overall health and homeostasis. During the lifecycle, several physiological alterations ensue throughout the metabolic system that attribute to functional decline. In this cross‐sectional analysis, a targeted metabolomic approach was applied to investigate the plasma metabolome of 151 young (n = 75) and older adults (n = 76). A corrected MANOVA model was generated, with such covariates as gender, BMI, and chronic condition score (CCS), to analyze the aging process of the two populations. Metabolites associated with impaired fatty acid metabolism were found to be most significant: palmitic acid (p < 0.001), 3‐hexenedioic acid (p < 0.001), stearic acid (p = 0.005), and decanoylcarnitine (p = 0.036). Derivatives of amino acid metabolism, 1‐methlyhistidine (p = 0.035) and methylhistamine (p = 0.027), were found to be increased in the younger population and several novel metabolites were identified, such as cadaverine (p = 0.034), 4‐ethylbenzoic acid (p = 0.029), and 3‐hexenedioic acid (p < 0.001). Principal component analysis was conducted and highlighted a shift in the metabolome for both groups. Pathway and enrichment analyses uncovered several impacted pathways that elucidate the metabolic alterations in the older population and aid in further explanation of the aging process. As a result, we offer a better understanding of the aging metabolome and potentially reveal new biomarkers for future study.
Borate Transporters Are Inhibited by the Stilbene‐Derived Inhibitor SITS
Authors: McGrath Lila , Collings Becca , Havill Nick , Thurtle‐Schmidt Bryan
Published: May 2022

Borate transport proteins regulate the availability of borate, an essential plant micronutrient that is toxic in excess. Borate transporters in plants and fungi share sequence and structural homology with the SLC4 transporters, which suggests they might share other key features. The archetypal member of SLC4 transporters is human Band 3, or Anion Exchanger 1 (AE1). AE1 is the most abundant membrane protein in red blood cells where it exchanges bicarbonate and chloride, and mutations in AE1 are linked to several diseases such as hereditary spherocytosis and renal tubular acidosis. We tested whether the S. cerevisiae Bor1 (ScBor1) and A. thaliana Bor4 (AtBor4) transporters share with human AE1 (HsAE1) a sensitivity to inhibitors derived from stilbene. We show that ScBor1 and AtBor4 are both specifically inhibited by SITS, a known inhibitor of HsAE1. We also demonstrate that a poorly conserved N‐terminal region in ScBor1 can be deleted without impeding ScBor1 function in vivo, establishing a common functional core between borate transporters and the membrane transport domains of SLC4 transporters. Lastly, we show that the N‐terminal tail does not contribute to oxidative crosslinking in lipid‐mediated dimerization, which is surprising given a recent structural prediction from the AlphaFold server. These results collectively show important similarities between plant and fungal borate transporters and HsAE1 and demonstrate that borate transporter similarities with SLC4 transporters extend beyond sequence and structure. Further studies will be required to establish the amino acids most responsible for dimerization in SLC4 transporters and their homologs.
Activation of the Soluble Guanylate Cyclase Increases 26S Proteasome Activities and Protects against Proteotoxicity in Cardiomyocytes
Authors: Cai Mingqi , Wang Xuejun
Published: May 2022

Background

The ubiquitin‐proteasome system (UPS) mediates the selective degradation of unwanted and unneeded proteins in the cell, playing crucial roles in protein quality control and diverse other cellular processes. Proteasome malfunction and proteotoxicity are implicated in the genesis of a large subset of heart diseases. Our laboratory has previously discovered that activation of the cGMP‐dependent protein kinase (PKG) primes the proteasome. Here we test the hypothesis that by increasing cGMP and PKG activity, soluble guanylate cyclase (sGC) activation activates the proteasome and thereby protects against proteotoxicity in cardiomyocytes.

Methods and Results

Compared with vehicle control (DMSO), treatment with an sGC activator (cinaciguat) in cultured neonatal rat cardiomyocytes (NRCMs) led to increases in the levels of Ser239‐phosphorylated vasodilator‐stimulated phosphoprotein (VASP) (2.17±0.07 vs. 1.0±0.20, p<0.0001), indicative of PKG activation. We then used adenoviral vectors expressing degron CL1‐fused green fluorescent proteins (GFPu, a proven UPS substrate) or red fluorescent proteins (RFP, a stable protein control) as a reporter system for UPS performance. Compared with DMSO, cinaciguat treatment reduced the GFPu/RFP ratio (0.59±0.06 vs. 1.0±0.18, p=0.0135) as revealed by western blotting, and shortened GFPu half‐life in cultured NRCMs as revealed by cycloheximide chase assays. Cinaciguat treatment decreased Thr41/Ser45‐phosphorylated β‐catenin, an endogenous substrate of the UPS (0.60±0.12 vs. 1.0±0.08, p=0.0014). These data demonstrate that sGC activation enhances UPS performance. Moreover, in‐gel proteasome activity assays followed by western blot analyses reveal that cinaciguat treatment increased the chymotrypsin like activities of 26S proteasomes (1.52±0.17 vs. 1.0±0.09, p=0.0019) without changing 26S proteasome assembly, showing that sGC activation enhances UPS performance via activating 26S proteasomes. We next used NRCMs with adenovirus‐mediated overexpression of a human‐disease‐linked misfolded protein CryABR120Gas a cell model of cardiac proteotoxicity. CryABR120G overexpression‐induced increases in LDH leakage and PKCδ cleavage (both indicative of cell injury/death) were significantly attenuated by cinaciguat treatment (LDH in media: 0.71±0.20 vs.1.44±0.26, p<0.0001); further MTT assays consistently showed cinaciguat promoted NRCMs viability (1.32±0.11 vs. 1.02±0.05, p<0.0001).

Conclusions

Activation of sGC with cinaciguat increases PKG activity, activates the 26S proteasome, facilitates UPS functioning, and thereby protects against proteotoxicity in cardiomyocytes.
Cardiac Adjustments During a Very Hot and Dry Heatwave Simulation in Older Adults
Authors: Watso Joseph C. , Belval Luke N. , Foster Josh , Cimino Frank A. , Orth Bonnie D. , MacNamara James P. , Sarma Satyam , Crandall Craig G.
Published: May 2022

Heatwaves are the leading cause of death among natural disasters in the United States and are predicted to increase in frequency, duration, and severity. During heatwaves, older adults (over 65 years old) have disproportionally greater morbidity and mortality, primarily from cardiovascular complications. However, it is unknown whether a very hot and dry heat wave simulation would impair cardiac function in older adults.

Purpose

We tested the hypothesis that three hours of exposure to a very hot and dry heat wave simulation would increase left‐ventricular contractility (s’) in older adults.

Methods

We assessed internal body temperature (ingestible telemetric pill and/or rectal thermistor), mean skin temperature (thermocouples), cardiac function (echocardiography), limb blood flow (brachial artery sonography) in eight healthy older adults (5 Female/3 Male; 70 ± 4 years; 26 ± 3 kg•m‐2) while they were exposed to a simulation of the 2018 Los Angeles heatwave for three hours. We measured hemodynamics in a temperate environment (~23 ºC) before repeating these measures after three hours of heat exposure in an environmental chamber (46 ± 1 ºC, 17 ± 1 % relative humidity). For ecological validity, participants performed seven bouts of exercise (3 METS for 5 minutes) dispersed across the three‐hour‐long heat exposure to simulate activities of daily living. Additionally, participants consumed 9 mL of 15 ºC (tap‐temperature) water per kilogram of body mass dispersed throughout the trial. We compared values before (BASE) or at the start (START) of heating with values obtained at the end of heating (END) using a Wilcoxon test for propagation velocity, limb blood flow and vascular conductance, and paired, two‐tailed t‐tests for all other variables.

Results

Internal body temperature (START: 36.8 ± 0.4, END: 38.2 ± 0.5 ºC, p<0.01) and mean skin temperature (START: 35.5 ± 1.3, END: 37.3 ± 0.7 ºC, p=0.02) increased during heating. Heart rate increased (BASE: 73 ± 19, END: 99 ± 40 bpm, p=0.04) and mean arterial pressure decreased (BASE: 90 ± 14, END: 77 ± 11 mmHg, p=0.03) during heating. Combined [septal & lateral] s’ (BASE: 8.2 ± 1.4, END: 11.3 ± 1.5 cm/s, p<0.01) increased during heating, for which changes from BASE to END were moderately, but non‐significantly, related to Δ internal body temperature (R2= 0.25, p= 0.21). Indices of left ventricular diastolic function did not change during heating (p>0.24 for E, A, E/A, combined e’, E/combined e’, propagation velocity, & iso‐volumetric relaxation time). Limb blood flow and vascular conductance increased ~four‐fold during heating (p<0.02 for both).

Conclusion

These preliminary data suggest that older adults increase left‐ventricular contractility to maintain stroke volume, potentially to compensate for increased limb vascular conductance, during three hours of exposure to a very hot and dry heatwave simulation.
Epicardial histone deacetylase 3 promotes myocardial growth through a novel microRNA pathway
Authors: Jang Jihyun , Li Deqiang
Published: May 2022

Establishment of the myocardial wall requires proper growth cues from nonmyocardial tissues. During heart development, the epicardium and epicardium‐derived cells (EPDCs) instruct myocardial growth by secreting essential factors including fibroblast growth factor 9 (FGF9) and insulin‐like growth factor 2 (IGF2). However, it is poorly understood how the epicardial secreted factors are regulated, in particular by chromatin modifications for myocardial formation. To understand whether and how histone deacetylase 3 (HDAC3) in the developing epicardium regulates myocardial growth, we deleted Hdac3 in the developing murine epicardium. Mutant hearts showed ventricular myocardial wall hypoplasia with reduction of EPDCs. The cultured embryonic cardiomyocytes with supernatants from Hdac3 knockout (KO) mouse epicardial cells (MECs) also showed decreased proliferation. Genome‐wide transcriptomic analysis revealed that Fgf9 and Igf2 were significantly down‐regulated in Hdac3 KO MECs. We further found that Fgf9 and Igf2 expression is dependent on HDAC3 deacetylase activity. The supplementation of FGF9 or IGF2 can rescue the myocardial proliferation defects treated by Hdac3 KO supernatant. Mechanistically, we identified that microRNA (miR)‐322 and miR‐503 were upregulated in Hdac3 KO MECs and Hdac3 epicardial KO hearts. Overexpression of miR‐322 or miR‐503 repressed FGF9 and IGF2 expression, while knockdown of miR‐322 or miR‐503 restored FGF9 and IGF2 expression in Hdac3 KO MECs. Our findings reveal a critical signaling pathway in which epicardial HDAC3 promotes compact myocardial growth by stimulating FGF9 and IGF2 through repressing miR‐322/miR‐503, providing novel insights in elucidating etiology of congenital heart defects, and conceptual strategies to promote myocardial regeneration.
A High throughput bioluminescent assay to monitor the activity of COVID‐19 Methyltransferases Capping Enzymes
Authors: Goueli Said A. , Hsiao Kevin A.
Published: May 2022

The recent pandemic outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‐Cov‐2) was first reported in Wuhan, China in late 2019 resulting in infection of over 259 million and death of over 5.17 world‐wide as of November 2021. In the USA, the number of diagnosed individuals reached 48 million with 92,000 Death cases. Despite the lower pathogenicity compared to SARS‐CoV and MERS‐CoV, the high infection rate of SARS‐CoV‐2 results in large numbers of hospitalizations and deaths worldwide.

The SARS‐Cov‐2 is an enveloped virus and belongs to the beta coronavirus family containing a large and complex positive–sense single stranded RNA genome (~30kb). It binds to human ACE2 receptor with high affinity via its spike protein (S) and membrane fusion leading to the release of its genomic RNA that replicates and produce higher number of sub‐genomic RNAs. The viral RNA is then capped by nsp 14 and nsp10/16, two nonstructural proteins that catalyze the methylation of RNA to limit its degradation by cellular 5’‐3’ exonuclease and evade host immune system. These enzymes play critical role in translation of the viral RNA and its replication and thus leading to viral survival.

We have used a bioluminescent high throughput enzyme assay for monitoring the activity of these enzymes in order to develop novel inhibitors which can be advanced for therapeutic treatment. We show that we can determine the activity of nanogram amounts of these enzymes and test the activity of these enzymes using different inhibitors, some of which are competitive with S‐adenosyl methionine the canonical substrate for these enzymes. We also show the effect of inhibitors that compete with the oligonucleotide substrate. Finally, we tested the effect of a peptide modulator of COVID‐2 on the activity of both nsp 10/16 and nsp 14. The assay is simple, homogenous, fast, and bioluminescent which provides a very robust platform for testing novel compounds on the viral methyltransferases leading to the generation of new drugs towards inhibiting the replication of COVID‐19.
Distinct Properties of Adipose Stem Cell Subpopulations Determine Fat Depot‐Specific Characteristics
Authors: Nahmgoong Hahn , Jeon Yong Geun , Park Eun Seo , Choi Yoon Ha , Han Sang Mun , Park Jeu , Ji Yul , Sohn Jee Hyung , Han Ji Seul , Kim Ye Young , Hwang Injae , Lee Yun Kyung , Huh Jin Young , Choe Sung Sik , Oh Tae Jung , Choi Sung Hee , Kim Jong Kyoung , Kim Jae Bum
Published: May 2022

In mammals, white adipose tissues are largely divided into visceral epididymal adipose tissue (EAT) and subcutaneous inguinal adipose tissue (IAT) with distinct metabolic properties. Although emerging evidence suggests that subpopulations of adipose stem cells (ASCs) would be important to explain fat depot differences, ASCs of two fat depots have not been comparatively investigated. Here, we characterized heterogeneous ASCs and examined the effects of intrinsic and tissue micro‐environmental factors on distinct ASC features. We demonstrated that ASC subpopulations in EAT and IAT exhibited different molecular features with three adipogenic stages. ASC transplantation experiments revealed that intrinsic ASC features primarily determined their adipogenic potential. Upon obesogenic stimuli, EAT specific SDC1+ ASCs promoted fibrotic remodeling, whereas IAT‐specific CXCL14+ ASCs suppressed macrophage infiltration. Moreover, IAT‐specific BST2high ASCs exhibited a high potential to become beige adipocytes. Collectively, our data broaden the understanding of ASCs with new insights into the origin of white fat depot differences.
Integrative therapies for amyotrophic lateral sclerosis disease using dynamic physiological systems
Authors: Nnake Ijeoma , Tulp Orien L. , Einstein George P.
Published: May 2022

Background

Amyotrophic Lateral Sclerosis (ALS) is a fatal motor neuron condition that is characterized by progressive loss of upper and lower motor neurons at the spinal or bulbar level with an incidence of about 1/100,000. ALS is categorized in two forms. The most common form is sporadic (90–95% of cases) which has no obvious genetically inherited component. The familial type of ALS (FAL5, represents ~10% of cases) is due to associated genetic dominant inheritance factors. The first onset of symptoms of ALS usually occurs between the ages of 50 and 65. The pathogenesis of ALS is unknown. There are two approved medications for ALS treatment: riluzole and edaravone, both of which have many reported side effects. ALS patients and their family members seek an effective therapy for treating the symptoms and/or delaying the progression of ALS.

Method

A comprehensive literature search consisting of 12 peer reviewed studies was conducted using PubMed, Medline and Nature review from inception to 2019, and meta‐analysis used to evaluate the findings. Amyotrophic Lateral Sclerosis diagnosis was determined using El Escorial criteria. Exposures to agriculture chemicals, heavy metals, electrical magnetic fields, types of diet, and physical activity were all examined for association with ALS. Also, use of integrative therapies (IT) were evaluated among the treatment options reviewed.

Results

The results of the study did not indicate that factors of diet, smoking or cardiovascular disease increase the risk of developing ALS. Vitamins and Chinese herbal decoctions, Chinese herbal compounds, massage therapy, and acupuncture were the 5 most commonly used IT reported. In the meta‐analysis reviewed, the most common reason for using IT was to treat weakness and fatigue in males (68.72% of males were IT users) and muscle atrophy in females (66.35% of females were IT users). Most of the effects of the IT therapies reported were improvements in subjective symptoms of the disorder.

Conclusion

This study could not identify smoking, physical activity, environmental exposure, occupational factors, or dietary habits as risk factors or protective factors for the onset or progression of ALS. ALS has multiple pathological mechanisms. Since integrative therapy contains various components which display multiple effects, it would be helpful in alleviating the pathological events affecting patients with ALS, thereby increasing the quality of life for the individuals and families of patients. However, more research must be performed regarding the efficacy and safety of integrative therapy or complementary and alternative therapy and clinical studies will be required to demonstrate the complimentary beneficial effects of integrative therapies in the management and treatment of ALS.
Autophagy Induction Via κ‐Opioid Receptor is Implicated in Stress‐Driven Synaptic Alterations
Authors: Georgoussi Zafiroula , Karoussiotis Christos , Sotiriou Aggeliki , Polissidis Alexia V. , Papavranoussi‐Daponte Danae , Symeonof Alexandra , Nikoletopoulou Vassiliki
Published: May 2022

Neuronal autophagy controls the quality of cytoplasmic proteins through degradation of important synaptic proteins and modulates synaptic organization and morphogenesis (1). Evidence has shown that G protein coupled receptors are direct sensors regulating the autophagic machinery (2) and opioid receptors regulate neuronal plasticity and neurotransmission with as yet unclarified mechanism (3,4). Using in vitro and in vivo studies, we demonstrated that κ‐opioid receptor (κ‐OR) agonists induce autophagy via a PTX‐sensitive G protein manner and identified the downstream components involved (5). Our molecular analysis also revealed a κ‐OR‐driven upregulation of becn1 gene through ERK1,2‐dependent activation of the transcription factor CREB in neuronal cells. Moreover, our studies demonstrated that sub‐chronic U50,488H administration in mice causes profound increases of specific autophagic markers exclusively in the hippocampus with a concomitant decrease of several pre‐ and post‐synaptic proteins such as spinophilin, PSD‐95 and SNAP25. Finally, using acute stress, a stimulus known to increase the levels of the endogenous κ‐OR ligand dynorphin, we are demonstrating that administration of the κ‐ΟR selective antagonist, nor‐binaltorhimine, blocks the induction of autophagy and the stress‐evoked reduction of synaptic proteins in the hippocampus. These findings provide novel insights about the essential role of autophagic machinery into the mechanisms through which κ‐OR and its signaling regulates brain plasticity.

References

1. Nikoletopoulou V, Papandreou ME, Tavernarakis N (2015) Cell Death Differ 22: 398‐407

2. Wauson EM, Dbouk HA, Ghosh AB, Cobb MH (2014) Trends Endocrinol Metab 25: 274‐2823.

3. Georganta EM, Tsoutsi L, Gaitanou M, Georgoussi Z (2013) J Neurochem 127: 329‐341

4. Kibaly C, Xu C, Cahill CM, Evans CJ, Law PY (2019) Nat Rev Neurosci 20: 5‐18

5. Georgoussi Z and Karoussiotis C (2019) FASEB J. Supplement Issue Vol.33
Transitioning from In Person to Online Human Anatomy: Student Perspectives from the COVID‐19 Pandemic
Authors: Kaufman Rachel E. , Patel Kush , Edmondson Anna
Published: May 2022

Introduction & Objective

In March 2020, medical schools around the country had to quickly transition from in person cadaveric anatomy curricula to an online distance learning format due to the COVID‐19 pandemic. This posed a challenge for students who had acclimated to learning anatomy inside the laboratory for the majority of their first year of medical school. The purpose of this study was to assess student perceptions of the abrupt transition from in person anatomy dissections and practical exams to an exclusively online format.

Materials and Methods

An anonymous survey was distributed to medical students from the Class of 2023 at the Medical College of Georgia at Augusta University (n=191) in February 2021. The survey assessed student perceptions of the impact of COVID‐19 shutdowns on their medical education. In total, 45 responses were recorded, and survey data was analyzed using SPSS software. Nonparametric methods were used due to the ordinal nature of the Likert scale responses. A Wilcoxon signed rank test was performed. In addition, focus groups were conducted with 11 medical students who had completed the survey.

Results

A majority of respondents (82.55%) stated that their learning and understanding of anatomy was worse after cancellation of in person anatomy lab dissections. In contrast, understanding of didactic lecture material was split, with 37.5% stating that online lectures had no impact on their learning and understanding of the material, 31.25% stating understanding was worse, and 25% stating it was better following transition to online‐only lectures. The results from the Wilcoxon signed rank test of Likert scale responses indicated that students perceived impact of cancelling in person anatomy lab as significantly worse compared to the impact of cancelling in person lectures (p<0.001). Focus group responses echoed this theme, with the loss of 3‐dimensional visual and tactile learning in laboratory cited most frequently by participants as a challenge with the transition to online anatomy.

Conclusion

Medical student respondents in the class of 2023 perceived online anatomy as inferior to in person laboratory sessions after the COVID‐19 shut‐down in March 2020. The transition from in person to online anatomy was more impactful on student understanding of material than the transition from in person to online didactic lectures. Of note, the students surveyed had completed the majority of their anatomy curriculum in person prior to the transition online.

Significance/Implication

The medical school shutdowns that occurred in March 2020 due to the COVID‐19 pandemic highlighted the importance of in person interaction with cadaveric specimens in anatomy education, especially in the context of how students were initially exposed to content. When possible, consideration should be given to learning approaches that students are familiar with and how changes to the curriculum will impact them.
Caffeine Induces Spontaneous Ventricular Tachyarrhythmias and Bidirectional Ventricular Tachycardia: Increased Vulnerability with Aging
Authors: Chen Victor , Choudhury Nibras , Zhang Youhua
Published: May 2022

Introduction

Caffeine is generally suspected to trigger or exacerbate cardiac arrhythmias in patients, but so far clinical data have been conflicting. We have demonstrated previously that caffeine plus dobutamine challenge can induce ventricular tachyarrhythmias in normal rats (Heart Rhythm O2 2020;1:359‐367). However, whether caffeine alone can induce cardiac arrhythmias has not been investigated. We hypothesize that caffeine alone could trigger spontaneous cardiac arrhythmias, which may be affected by aging and sexes. In this study we have investigated the effect of caffeine on spontaneous cardiac arrhythmias in younger and older adult rats of both sexes.

Methods

This study used Sprague‐Dawley rats. Younger (5‐month‐old) and older (1‐year‐old) adult rats of both sexes were enrolled. The study consisted of the following groups: 5‐month‐old male rats (younger male, n=8) and 1‐year‐old male rats (older male, n=9), 5‐month‐old female rats (younger female, n=6) and 1‐year‐old female rats (older female, n=5). These rats received caffeine (80mg/kg, IP) injection. In addition, a group of 5‐month‐old rats (both sexes, n=8) receiving saline injection without caffeine served as the control group. Surface electrocardiogram (ECG, standard Lead II) was continuously monitored and recorded during the experiments.

Results

No arrhythmia was induced in the control group with saline injection. Caffeine injection induced ventricular tachyarrhythmias in 8/9 older male rats, while only in 2/8 younger male rats (younger versus older male rats, p=0.0152, Fisher's exact test). Similarly, ventricular arrhythmias were induced in 5/5 older female rats, and only in 1/6 younger female rats (older versus younger female rats, p=0.0152). There were no significant differences in male versus female rats in both age groups. Induced ventricular arrhythmias include various premature ventricular contractions (PVC, Figure‐Panel A) in all rats, monomorphic ventricular tachycardia (VT, Panel B) in 3 rats and polymorphic VT and bidirectional VT (Panel C) in all rats. No atrial arrhythmia was observed.

Conclusion

Caffeine can induce spontaneous ventricular arrhythmias in normal rats, and the younger rats are more resistant to arrhythmia induction. Arrhythmia inducibility increases significantly in older rats. There is no sex difference in caffeine induced ventricular arrhythmias. Although different types of ventricular arrhythmias are induced, the characteristic bidirectional VT is highly prevalent among the caffeine induced arrhythmias and no atrial arrhythmia was observed.