bluuebunny/crossref_metadata_2025_split huggingface dataset:
Membrane channel gene expression in costal cartilage from patients with chest wall deformities
Authors: Asmar Anthony , Barrett‐Jolley Richard , Kelly Robert , Tanaz Royena , Stacey Michael 
Published: November 2023

Chondrocytes form permanent cartilagein joints and ribs. Although much work has been undertaken on joint cartilage with respect to osteoarthritis, little is known about rib, or costal, cartilage. Inherited disorders of costal cartilage include pectus excavatum(PE) and pectus carinatum (PC), where the sternum is either depressed towards the spine, or protrudes outwardly forming a ‘pigeon chest’ respectively. In severe case there are profound consequences on heart and lung function. The occurrence of these disorders is approximately 1 in 400–1,000 with a strong male bias. Key to chondrocyte function is the ability to respond to mechanical loads with changes of metabolic activity. This mechano transduction property is, in part, mediated through the activity of a range of constitutively expressed transmembrane channels; ion channels, gap junction proteins, and porins. Appropriate expression of ion channels has been shown essential for production of extracellular matrix and differential expression of transmembrane channels is correlated to other musculoskeletal diseases such as osteoarthritis and Albers‐Schönberg. In this study the objective was to measure consistency of gene expression between channelomes of chondrocytes from patients with chest wall deformities compared to apparentlynormal samples of costal cartilage obtained from individuals with no known history of chest wall deformity. Gene expression was also compared to myocardial cells with well‐defined channelome expression. In our preliminary data we found 23 genes for different ion channels commonly expressed between costal chondrocytes. Interestingly, there were five ion channel genes observed which are characteristic to chondrocytes from chest wall deformities and five observed only in control chondrocytes. mRNA expression of the gap junction/innexin‐like genes;Panx1, Cx43 and Cx45 was also detected. In conclusion, this data highlights similarities and differences between chondrocyte membrane channel gene expressions in cells derived from patients versus control cost alcartilage. Overall, the data shows high expression of a range of mechanically and metabolically sensitive membrane channels suggesting that chondrocytemechanotransduction may play an important role in chest wall deformity.Support or Funding InformationResearch reported in this publication was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institute of Health under the award number R21AR063334. The content is solely the responsibility of the authors and does not necessarily represent the views of the NIH. We also acknowledge partial support from the Breeden Adams Foundation of Norfolk, VA, USA.
Modulation of the BK Channel During Acute Spinal Cord Injury is Neuroprotective
Authors: JACOBSEN MARIANNE C , Lett Kristin A , Karnitsky Max , Arwini Balsam M , Barden John M , Buttigieg Josef 
Published: November 2023

Spinal cord injury results in significant neuronal and glial cell death resulting in impaired neurological and motor function. While there are often surviving axonal tracts, these are frequently dysmyelinated or demyelinated. Key to this pathology is uncontrolled Ca2+ entry, resulting in excitotoxicity and cell death. We propose that by activating mechanisms attenuating global depolarization and limiting Ca2+ entry, we can reduce neuronal death and significantly improve neurological and motor function. To this effect, we previously demonstrated that the large‐conductance, voltage and Ca2+‐activated K+ (BK or Maxi K+) channel is altered after SCI, and may play a part in the neuropathology of SCI. In this study, we set out to explore whether the use of a BK channel activator, Isopimaric acid (ISO), is neuroprotective post spinal cord injury. Wister rats received a 25‐g clip compression injury at the T7 levels for 1 min. One hour post‐surgery, they were administered ISO (120 μM), Ibeurotoxin (IbTx; 100nM), or a vehicle control via mini‐osmotic pump. Complete gait analysis was performed using two‐dimensional motion capture by filming rats on a weekly basis for 8 weeks. Compound Action Potentials (CAP) and high frequency conduction experiments were performed on spinal cords 8 weeks post surgery. Finally, the size of the injury site, loss of myelination, and cell death were assessed using immunohistochemistry (IHC). Complete gait analysis suggests that treatment with ISO improves motor function in our test model. ISO treated animals were able to recover gait function to a greater extent than IbTx and control animals. While the IbTx treated rats also demonstrated an improvement in complete gait function, their recovery was delayed and not of the same magnitude as ISO treated animals. This finding was further supported in our electrophysiology and IHC experiments. In our CAP experiments we find that there is a significant difference between all three groups. Additionally, we found preservation or re‐establishment of axonal tracts and myelination in our IHC experiments. In conclusion, activation of the BK channel during acute SCI may be a novel therapeutic target for acute spinal cord injury. Further studies are required to determine if modulation of the BK channel in chronic injury is beneficial for recovery, and to understand the mechanisms by which this ion channel may be working during spinal cord injury repair.Support or Funding InformationSaskatchewan Health Research Foundation
Proposed Mechanism for Post‐Exercise Weakness in Hypokalemic Periodic Paralysis
Authors: Cannon Steve C , Mi Wentao , Wu Fenfen 
Published: November 2023

Hypokalemic periodic paralysis (HypoKPP) is a dominantly inherited channelopathy of skeletal muscle in which recurrent episodes of severe weakness are often provoked by environmental triggers such as carbohydrate ingestion, K+ loss, or exercise. Remarkably, the mutations that cause HypoKPP occur almost exclusively at arginine residues in the S4 voltage sensor domains of the L‐type Ca channel (CaV1.1) or the voltage‐gated sodium channel (NaV1.4). These R/X mutations of S4 produce an anomalous conduction pathway that is permissive (open) at hyperpolarized potentials. This so‐called gating pore leakage current renders the muscle fiber susceptible to anomalous depolarization of Vrest in low K+ (e.g. 2 to 3 mM). Depolarized fibers are refractory to the generation of action potentials, resulting in loss of force. While this low K+ induced basis for episodic weakness is well established, the mechanism by which weakness occurs within minutes of resting after strenuous exercise is completely unknown.We tested the hypothesis that acidosis is a trigger for exercise‐induced attacks of weakness in HypoKPP. This notion was explored in our previously developed knock‐in mutant mouse models of HypoKPP (NaV1.4‐R669H and CaV1.1‐R528H). The soleus muscle was mounted in an HCO3 buffered tissue bath and maximal isometric force was measured during tetanic stimulation (100 Hz, 40 pulses). Acidosis was imposed by bath exchange with a solution equilibrated to 25% CO2 (pH 6.8), compared to baseline 5% (pH 7.4). Acidosis was well tolerated for WT and HypoKPP muscle during a 20 min exposure to 25% CO2. Upon return to 5% CO2, however, there was a marked transient decrease in force for HypoKPP muscle but not for WT. Myoplasmic pH homeostasis in response to the 25% CO2 challenge was indistinguishable for WT and HypoKPP muscle, as measured with BCECF. We propose the transient weakness is caused by a pH‐dependent rise of myoplasmic Cl. Acidosis reduces the ClC‐1 conductance (GCl), thereby limiting Cl efflux, while influx via the NKCC cotransporter produces a slow rise of myoplasmic Cl. A rapid correction of pH quickly increases GCl which depolarizes the fiber because of the shift of ECl. In support of this hypothesis, inhibition of NKCC with bumetanide completely prevents the post‐acidosis loss of force. Model simulations show myoplasmic Cl accumulation and susceptibility to depolarization are greater for HypoKPP muscle than WT due to the gating pore current.We propose the post‐exercise weakness in HypoKPP muscle is caused by a shift of Cl into muscle while GCl is low during acidosis, followed by depolarization if GCl recovers quickly. A slower recovery from acidosis my allow the Cl gradient to return to baseline before a full recovery of GCl, thereby reducing the risk of paralysis as patients have reported with warm‐down after exercise.Support or Funding InformationSupported by the National Institutes of Arthritis, Musculoskeletal, and Skin Diseases of the NIH (Grants AR42703 and AR063182).
Heparanase may contribute to idiopathic pulmonary fibrosis via nuclear translocation of cleaved heparan sulfate proteoglycans
Authors: Yang Yimu , Lara Abigail , Rutebemberwa Alleluiah , Schmidt Eric 
Published: November 2023

Heparanase (HPSE) is an endo‐β‐glucuronidase capable of cleaving heparan sulfate (HS) side chains of heparin sulfate proteoglycans (HSPGs), important components of the extracellular matrix (ECM). HPSE has important roles in a variety of biological processes, including angiogenesis, inflammation, wound healing and metastasis. Little is known about HPSE and human idiopathic pulmonary fibrosis (IPF). Using immunohistochemistry, we noted that 6/6 human IPF lung biopsies expressed HPSE in vascular smooth muscle (VSM), endothelial cells and macrophages. In VSM and endothelium, heparanase was localized in both of the cytoplasm and nucleus. To determine if expressed HPSE was enzymatically active, we, immunostained with anti‐HS mAb 3G10 (which detects remnant HS fragment cleaved by HPSE). An abundance of 3G10 immunostaining were found in the nucleus of the most type of the cells. We hypothesized that prolonged HPSE activity cleaves HS in the ECM/cell surface, inducing an internalization and nuclear translocation of HSPGs. These findings were confirmed using mouse lung fibroblasts treated with heparinase‐III, a HPSE analog, which demonstrated nuclear translocation of 3G10 positive (HS‐fragmented) proteoglycans. Our findings suggest that nuclear HS/HSPGs may be directly involved in regulating biological processes including transcription and cell cycle progression, leading to the abnormal cell proliferation and wound repair characteristic of IPF.Support or Funding InformationK08 HL105538
MED28 regulates TNFα‐ and CoCl2‐mediated migration and invasion in human non‐small cell lung cancer (NSCLC) cells
Authors: Hsieh Nien‐Tsu , Huang Chun‐Yin , Cheng An‐Chin , Lee Ming‐Fen 
Published: November 2023

Growing evidence indicates that chronic inflammation and oxidative stress are involved in the malignant progression. Epithelial tumors undergo epithelial‐mesenchymal transition (EMT) and remodel extracellular matrix to acquire a motile and invasive phenotype. MED28, a Mediator subunit for transcriptional activation, is also found highly expressed in several types of epithelial tumors. Our laboratory has recently reported that MED28 upregulates cell growth in both human breast cancer and colorectal cancer cells, and MED28 modulates migration and invasion in MCF7 and MDA‐MB‐231 human breast cancer cells. The present study was to explore the potential role of MED28 in inflammation‐ and oxidative stress‐induced EMT and migration in A549 human non‐small cell lung cancer (NSCLC) cells. Cellular oxidative stress was increased upon the addition of either TNFα or CoCl2. Both TNFα and CoCl2 induced EMT and enhanced migration as evidenced by increasing mesenchymal cell types and Matrigel invasion, respectively, and accompanied by concomitantly upregulating the target genes and the functional activity of NFκB. However, these upregulation events were attenuated upon MED28 knockdown. Out data indicate that MED28 modulates oxidative stress, EMT, and invasion in human NSCLC cells, further strengthening a critical role of MED28 in cancer development.Support or Funding InformationThis work was supported by the grant NSC102‐2320‐B‐309‐001‐MY3 to M‐F Lee.
Effects of calreticulin on FUT1 expression and beta1 integrin fucosylation in different cancer cells
Authors: Weng Yi‐Cheng , Chien Yin‐Chieh , Lu Kuan‐Ying , Lee Hsinyu 
Published: November 2023

Calreticulin (CRT) is a multifunctional ER chaperon protein. We had demonstrated that knockdown of CRT may suppress cell proliferation and migration in J82 bladder cancer cells. We further revealed that CRT stabilized the mRNA of fucosyltransferase1 (FUT1), which leads to an enhancement of fucosylation and the subsequent activation of beta1 integrin. Previous studies had demonstrated that knockdown of CRT suppress cell proliferation and migration in both PC3 prostate cancer cells and AGS gastric cancer cells. However, the effects of CRT on FUT1 expression and beta1 integrin fucosylation have not been investigated in these cells.In this study, we demonstrated that knockdown of CRT decreased the expression levels of FUT1 in PC3 cells and AGS cells. Furthermore, the fucosylation levels of beta1 integrin were significantly down regulated in these CRT knockdown cells. However, mRNA stability of FUT1 was not affected in either cell lines. These results suggested that CRT might affect the fucosylation of beta1 integrin in both PC3 cells and AGS cells. However, a different molecular mechanism was involved while compared to J82 bladder cancer cells. Taken together, our observations imply that CRT may regulate FUT1 expression differently between different cancer cells.
Inhibition of β‐Catenin Signaling by 3‐Acetylaltholactone in Cancer Cells
Authors: Boonmuen Nittaya , Chairoungdua Arthit , Tuchinda Patoomratana , Piyachaturawat Pawinee 
Published: November 2023

Wnt/β‐catenin signaling pathway is a complex protein interaction network which plays important functions in cell proliferation, survival and differentiation during animal development and in disease conditions. In Wnt pathway, binding of Wnt ligand to its receptors at the plasma membrane results in inactivation of the β‐catenin destruction complex and promotes the accumulation of β‐catenin translocation from cytoplasm into the nucleus to initiate the transcription of Wnt‐responsive gene expression by binding with TCF/LEF transcription factor. The aberrant regulation of Wnt/β‐catenin signaling has been found to associate with many human diseases including cancers. Therefore, it has been highlighted as a promising target for anti‐cancer drugs. In the present study, we reported the inhibitory effect of 3‐acetylaltholactone, a plant‐derived compound from Goniothalamus sp on the Wnt/β‐catenin signaling pathway in cancer cells. The compound inhibited growth of breast cancers (MCF‐7, and MDA‐MB‐231) and endometrial adenocarcinoma (Ishikawa cell lines). It effectively decreased the expression of β‐catenin protein in breast cancer cells and inhibited TCF/LEF mediated transcriptional activity in HEK293 cells. In addition, 3‐acetylaltholactone also decreased the mRNA expressions of Wnt signaling target genes in MCF‐7 cells. Moreover, it inhibited cell migration by using wound healing assay in MDA‐MB‐231 cells, a highly metastatic human breast carcinoma cell line. In conclusion, these results suggest that 3‐acetylaltholactone mediates anticancer effect on breast cancer cells through inhibition of the Wnt/β‐catenin signaling pathway.Support or Funding InformationSupported by Mahidol University, TRF through RGJ‐ Ph.D. Program (PHD/0170/2552 to PP and NB), and IRN58W0004.
Spinal Oxygen Sensors in Larval Amphibians
Authors: Evanger Iver J , Reed Mitchell D , Wilson Richard JA , Dutschmann Mathias , Taylor Barbara E , Harris Michael B 
Published: November 2023

We have recently identified mammalian spinal preganglionic sympathetic neurons as spinal oxygen sensors (SOS). These cells are excited by hypoxia, silenced by hyperoxia, and contribute to oxygen‐sensitive sympathetic responses important for cardiovascular regulation. In general, terrestrial vertebrates experience acute or chronic hypoxia only during pathophysiological states. In contrast, aquatic vertebrates routinely experience environmental hypoxia and hypoxic sensitivity is critical to homeostatic regulation. The aim of the current study is to identify SOS neurons in aquatic larval amphibians. We test the hypothesis that endogenously hypoxia‐sensitive neurons are present in the spinal cords of larval bullfrogs (Lithobates catesbeianus). Spinal cords were isolated from bullfrog tadpoles and incubated for 8 hours in either artificial cerebrospinal fluid or high Mg/low Ca solution to synaptically maintain or isolate cells. Preparations were then exposed to either hyperoxia, normoxia or hypoxia (PO2 of 700, 300 or 100 mmHg respectively) for 3 hours, after which tissues were fixed, sliced and stained to reveal early gene protein expression (c‐Fos) characteristic of cellular activation. Results illustrate the presence of hypoxia‐activated neurons in both synaptically intact and isolated preparations, indicating SOS neurons in amphibian spinal cords. We are characterizing the identities of these cells.Support or Funding InformationWork reported in this publication was supported by the National Heart Lung and Blood Institute and National Institute of General Medical Sciences of the National Institutes of Health under awards 1R15HL126105, 1SC2GM112570 and three linked awards number RL5GM118990, TL4GM118992 and 1UL1GM118991. Additional support was provided by the Natural Science and Engineering Research Council of Canada, the Canadian Institutes of Health Research and Alberta Innovates ‐ Health Solutions (RJAW) and the Australian Research Council (MD). The work is solely the responsibility of the authors and does not necessarily represent the official view of the National Institutes of Health or any other funding body.
Relative Blood Flow and Cardiac Output in Embryos of the Snapping Turtle Chelydra serpentina (Reptilia; Chelonia)
Authors: Sartori Marina R. , Kohl Zachary F. , Abe Augusto S. , Taylor Edwin W. , Crossley Dane A. 
Published: November 2023

In embryos from egg‐laying amniotic vertebrates gas exchange takes place over the chorioallantoic membrane (CAM), an extra‐embryonic circulation analogous to the mammalian placenta, and the oxygen obtained from the environment is convectively transported to the tissues of the developing embryo. Blood perfusion of the CAM (QCAM) and embryonic (QEMB) circulation can be regulated through blood shunts to or from each location. We used colored polystyrene microspheres to measure relative distribution of blood flow between QCAM and QEMB of the snapping turtle, Chelydra serpentina at different points of incubation at 30°C. We examined the embryonic capacity to regulate and redistribute the fractions of cardiac output by α‐blockade and acute 10% hypoxia exposure. Absolute flow was estimated based on measurements of arteriovenous oxygen difference (A‐V diff) according to the Fick Principle. QCAM was 9 (0.33 ml/g/min), 31 (0.17 ml/g/min), and 26% (0.07 ml/g/min) and QEMB was 84 (3.08 ml/g/min), 66 (0.36 ml/g/min), and 72% (0.19 ml/g/min) at 50, 70, and 90% of incubation, respectively. Flow directed to the yolk remained relatively low in all periods. α‐blockade had no influence on blood flow redistribution. Acute hypoxia elicited a bradycardia and a redistribution of the cardiac output fractions among embryonic tissues. QCAM was reduced (from 37% to 23%), and flow increased both to the liver (from 3% to 6%) and to the brain (from 0.8% to 2%) at 70% of incubation. At 90%, flow to the brain doubled during hypoxia. Our results suggest that cardiac output distribution during normoxia is preferentially directed to specific tissue beds, likely dictated by different oxygen demands during tissue differentiation and growth. Embryonic snapping turtles also showed a marked capacity of blood flow regulation during acute hypoxia, primarily protecting flow to the brain, an oxygen sensitive organ.Support or Funding InformationFAPESP 2014/01666‐5
Arterial PO2 Values Vary Dramatically During Diving and Surface Activities in the Freshwater Turtle (Trachemys scripta)
Authors: Williams Cassondra L , Hicks James W 
Published: November 2023

Mammals and birds maintain a narrow range of arterial PO2 values to preserve near complete O2 saturation. Since arterial blood gases in mammals and birds are tightly coupled with lung gas values, this is accomplished through changes in ventilation. In reptiles, pulmonary and system circulations are not completely separated and thus, cardiac shunts play a role in arterial blood gas values. Increases or decreases in the degree of right to left shunting (blood flow bypassing the pulmonary system) will immediately alter admixture and arterial PO2 can change rapidly despite stable ventilation. Further, anoxia‐tolerant reptiles, such as the red‐eared slider, may not need to maintain high arterial PO2 values. As a result, blood oxygen levels may vary more than in mammals and birds during diving as well as during other activities. To investigate this question, we continuously measured arterial PO2 in undisturbed, untethered red‐eared sliders (Trachemys scripta) over a 48‐hour period. Our hypotheses were (1) during routine activities, arterial PO2 values will vary but remain at or above 40 mmHg (75% O2 saturation) and (2) end of dive arterial PO2 values will be lower with longer submergences. Six adult red‐eared sliders (1546 ± 144g) were kept in tanks filled with 25°C water in a 25°C room. PO2 electrodes were surgically implanted in the carotid artery of anesthetized turtles. A self‐contained, waterproof data logger attached to the PO2 electrode was programmed to record PO2 at 1 Hz and epoxied to the carapace. After recovery, turtles were returned to the tank where they could freely swim and bask on a platform warmed by a heat lamp. Turtle behavior was recorded using a surveillance camera placed above the tank. Data were collected and analyzed. All procedures were approved by the University of California (IACUC #2011‐2995). Arterial PO2 during routine activities varied dramatically and individual PO2 values were often less than 40 mmHg. Mean PO2 values for each activity were: 22–42 mmHg for resting underwater; 23–55 mmHg while resting at surface; 29–49 mmHg during basking; and, 28–41 mmHg while swimming. Minimum PO2 values during surface events, basking, and swimming were often as low as minimum vales during submergences. End of submergence PO2 values varied dramatically from 2.7 to 51.7 mmHg and were significantly related to duration in only two turtles (p=0.007, 0.009). These results suggest freely diving, undisturbed T. scripta do not tightly regulate arterial O2 levels or maintain stable high arterial PO2 values even at the surface. The drive to maintain high arterial PO2 levels may be absent in these turtles due to their high tolerance to hypoxia and minimal metabolic demands.Support or Funding InformationThis research was funded by NSF IOS 1121324 (to J. Hicks). C.L.W. was supported in part by a National Institute of Health grant (NIH‐NIAMS T32AR047752 to V. Caiozzo).