bluuebunny/crossref_metadata_2025_split huggingface dataset:
Histone Deacetylase Inhibition Increases Glycerol Uptake in Normal and Hyperglycemic Conditions in Human Corneal Epithelial Cells
Authors: Melnyk Samuel , Choudhary Vivek , Lu Xiaowen , Chen Zhong , Watsky Mitchell , Bollag Wendy 
Published: May 2024

Delayed corneal wound healing, such as is seen in diabetes, can lead to visual impairment. Diabetes afflicts over 30 million Americans and leads to multiple comorbidities. Histone deacetylase (HDAC) expression and activity are increased in diabetes in correlation with an upregulation of inflammatory molecules and reactive oxygen species (ROS). HDACs have been previously found to suppress the expression of the glycerol channel aquaporin-3 (AQP3) in epithelial cells of the skin, the epidermal keratinocytes. Global deletion of AQP3 in mice has been found to delay corneal wound healing. We hypothesized that hyperglycemic conditions would decrease AQP3 levels and function while increasing the expression of HDAC(s), ROS scavenger proteins, and inflammatory mediators in human corneal epithelial cells (HCECs). HCECs were incubated for 48-hours in high glucose (25.5 mM) or normal glucose (~5.0 mM osmotically matched by mannitol) conditions. Under hyperglycemic conditions, the mRNA expression of interleukin-1α and -1β was significantly elevated, providing evidence for a pro-inflammatory effect of acute hyperglycemia in HCECs. Under these conditions, there was a significant increase in the mRNA expression of the ROS scavenger genes, superoxide dismutase-1 and -2 and peroxiredoxin-3 and -6, suggesting a compensatory response to an increase in ROS generation. Under acute hyperglycemic conditions, HDAC3 and HDAC8 mRNA expression also tended to increase while HDAC1 and HDAC2 mRNA levels remained unchanged. Although an upregulation of HDAC expression would be predicted to decrease AQP3 expression, AQP3 mRNA and protein expression levels were also unchanged. In addition, acute hyperglycemia (48 hours) did not alter glycerol transport into the HCECs, as measured by their uptake of radiolabeled [14C]-glycerol. However, HDAC inhibition using the broad-spectrum inhibitor SAHA for 24 hours increased [14C]-glycerol uptake under both normoglycemic and hyperglycemic conditions, suggesting that HDAC activity plays a role in AQP3 function. Overall, acute hyperglycemic conditions were pro-inflammatory and led to increased expression of ROS-scavenging genes; hyperglycemia also tended to upregulate HDAC expression, although without affecting AQP3 expression. On the other hand, HDAC inhibition increased glycerol uptake, an indicator of AQP3 function, suggesting an ability of HDAC activity to regulate AQP3 glycerol transport activity. National Institutes of Health/National Eye Institute award #R01EY030576 (to MW and WBB) VA Merit #BX005055 (to WBB). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
miRNA-221 and -222 increase in exosomes upon insulin stimulation of human vascular smooth muscle cells lacking the insulin-like growth factor 1 receptor
Authors: Bradford Angelle , Woods T. Cooper 
Published: May 2024

As a result of increased vascular inflammation, patients with Type 2 diabetes experience a near 4-fold increase in their risk for heart attack and stroke. miR-221 and -222 are two microRNAs that are upregulated in the vasculature of Type 2 diabetic patients. miR-221/222 act by downregulating the cyclin-dependent kinase inhibitor, p27Kip1, in vascular smooth muscle cells (VSMCs) and exosome-mediated proinflammatory effects on endothelial cells and macrophages. Loss of the insulin-like growth factor receptor (IGFR) in VSMCs can unmask the insulin receptor (IR) and increase insulin signaling. We have demonstrated that the loss of IGFR, coupled with physiological insulin stimulation, promotes an increased expression of miR-221/-222 in murine VSMCs. Respectively, miR-221/222 content in VSMC-derived exosomes increases and p27Kip1 mRNA expression decreases in VSMCs. We asked whether the effect of loss of IGFR in human coronary artery smooth muscle cells (HCASMCs) would also lead to an increase in miR-221/-222 content of VSMC-derived exosomes. Transfection with a CRISPR-cas9 plasmid targeting IGFR resulted in a 50% decrease in IGFR mRNA in HCASMCs, when compared to transfection with negative control CRISPR plasmids. Droplet digital PCR was used to measure expression of miR-221 and miR-222 in the exosomes derived from both sets of HCASMCs. There was no change in the miR-221/222 content of exosomes derived from HCASMCs transfected with the negative control CRISPR following stimulation with 1nM insulin (7.27± 4.75 vs. 11.33 ± 1.09 copies of miR-221 and 6.43 ± 0.43 vs. 4.68 ± 0.02 copies of miR-222). In contrast, there was a 2 to 3-fold increase in miR-221/222 content in exosomes that were derived from HCASMCs with IGFR knockdown following stimulation with 1nM insulin (14.96 ± 0.3 vs. 35.66 ± 3.08 copies of miR-221 and 9.12 ± 1.19 vs.15.44 ± 5.36 copies of miR-222). We conclude that loss of IGFR coupled with physiological insulin stimulation increases the miR-221/222 content of exosomes of HCASMCs, recapitulating the effects of IGFR loss seen in murine VSMCs as well as the effects of diabetes on VSMCs. This model system will allow additional studies connecting the loss of IGFR to the cardiovascular complications of diabetes. Tulane University School of Medicine, Biomedical Sciences Program. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Topographical distribution and morphology of TH-IR and VAChT-IR axons in the antrum, pylorus, and duodenum of rats
Authors: Chen Jin , Bendowski Kohlton T. , Zhang Yuanyuan , Cheng Zixi Jack 
Published: May 2024

The autonomic nervous system plays an essential role in controlling gastrointestinal functions including a variety of physiological functions such as the regulation of motility, gut secretion, and vascular flow. Tyrosine hydroxylase (TH) and vesicular acetylcholine transporter (VAChT) are commonly used markers for sympathetic and parasympathetic innervation, respectively. However, the regional distribution and morphology of TH-IR and VAChT-IR axons in the submucosa and mucosa are not well documented. In this study, the rat antrum-pylorus-duodenum (APD) were transversely and longitudinally sectioned. A Zeiss M2 imager was used to scan the serial sections of each APD (each section montage consisted of 50–100 all-in-focus maximal projection images). To determine the detailed structures of TH-IR and VAChT-IR axons, we used the confocal microscope to scan the regions of interest. We found that (1) TH-IR axons innervated the muscular, submucosal, and mucosal layers. In the muscular layer, the submucosa and the mucosa, TH-IR varicose axons innervated the muscles and innervated blood vessels. In the villi, TH-IR axons were presented. (2) VAChT-IR axons heavily innervated the muscular, submucosal, and mucosal layers. In the muscular layer, VAChT-IR varicose axons densely innervated the muscles and myenteric neurons were VAChT positive. In the submucosa and mucosa, VAChT-IR axons innervated as well. In the villi, VAChT-IR axons were densely innervated. (3) TH-IR and VAChT-IR axons were found not co-localized in the muscular, submucosal, and mucosal layers. This work provided a comprehensive view of the distribution and morphology of TH-IR and VAChT-IR axons in the APD at single cell/axon/varicosity scale. This data will be used to create a 3D mapping of the TH-IR and VAChT-IR axons innervation of the APD in rats. This study was supported by NIH HEAL/SPARC U01 NS113867-01 and NIH R15HL137143-01A1. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Effcacy of a chimeric PlGF derived protein for the management of preeclampsia
Authors: Chapman Heather , Moore Kyle , Bidwell Gene , George Eric 
Published: May 2024

Preeclampsia (PE) is one of the most common complications of pregnancy, affecting ~5-7% of pregnancies. Hallmarked by new onset hypertension and maternal endothelial dysfunction, PE is believed to be caused by insuffcient blood flow to the placenta. This causes the release of factors into the maternal circulation; notably the soluble VEGF receptor sFlt-1, which antagonizes the effects of VEGF in the endothelium. Placental growth factor (PlGF) is a VEGF family member produced by the placenta that only binds to the Flt-1 receptor and has little inherent angiogenic activity. We hypothesized that administration of a stabilized chimeric PlGF-derived protein (ELP-PlGF) would antagonize sFlt-1 in a rodent model of PE, and help resolve the maternal symptoms. We therefore utilized the reduced uterine perfusion pressure (RUPP) model of placental ischemia. RUPP animals exhibited a significant increase in blood presssure (99 vs 118 mmHg p<005), while RUPP animals treated with ELP-PlGF demonstrated significantly attenuated hypertension (105mmHg, p<0.05). Likewise, RUPP animals treated with ELP-PlGF showed decreased placental sFlt-1 (512 vs 308 pg/mg, p<0.05), and plasma sFlt-1 by western blot (13877 vs 6860 AU, p<0.05). Further, vascular preproendothelin expression from the aorta decreased 60% between RUPP and RUPP treated animals. Taken together, these results suggest that PlGF-based therapeutics could be a viable approach to the management of PE, and this formulation demonstrates significant effcacy in vivo in a relevant animal model. This work was partially supported by NIH grants P01HL51971, P20GM104357, and R01HL137791. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Cellular Redox Status of Dermal fibroblasts as a Model to Explore Hypoxia Responses Across Diverse Mammals
Authors: Douglas Micaah , Klink Amy C , Montenegro Janessa , Madelaire Carla , Hindle Allyson G 
Published: May 2024

Specializations in energy production pathways can define phenotype in mammals, enabling resilience to environmental stressors and survival in extreme habitats. Most mammals rely on oxygen-based mitochondrial respiration to sustain high rates of ATP production necessary for homeothermy; oxidative phosphorylation is fueled by donation of reducing equivalents (NADH, FADH2) to the electron transport chain. As such, relative redox levels within the cell (NAD+/NADH ratio) indicate cell health and metabolic status. In hypoxic conditions, cells can experience reductive stress, evidenced by a buildup of NADH and altered NAD+/NADH ratio. We are using primary dermal fibroblasts isolated from skin biopsies in n=9 species to compare metabolic changes via the ratio between NAD+ and NADH when exposed to 0.5% O2 for 6-h and 24-h. Species were selected to encompass diverse phylogeny as well as to include species that are adapted to low oxygen environments (high altitude gelada baboons, diving humpback whales and Weddell seals). Control species without adaptation to hypoxic environments included human, dromedary camel, little brown bat, honey badger, and rhinoceros. We expect fibroblasts from species adapted to living with variable oxygen availability to have more stability in NAD+/ NADH ratios when exposed to hypoxia in cell culture compared to those from species that are not adapted to low oxygen environments. We quantified NAD+ and NADH following exposure to hypoxia as well as control normoxic samples. Preliminary data with n=3 biological replicates per species show that fibroblasts from the control animals display significant differences in NAD+/NADH ratio between normoxic and hypoxic treatments (Kruskal-Wallis test, p=0.01), however, there are no significant differences in the ratios presented for tolerant animals (Kruskal-Wallis test, p=0.518). This finding supports our hypothesis that animals adapted to low oxygen reduce variability in the NAD+/NADH ratios. Understanding the metabolic patterns when cells are exposed to reduced oxygen levels can provide a framework for estimating a species resilience to environmental variation. Funded by NSF #2022046, CSUN-OUR Summer Undergraduate Fellowship. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Diet Shifts Alter the Activity and Distribution of Digestive Enzymes in an Herbivorous Fish
Authors: Rafanan Kirsten , Herrera Michelle , German Donovan , Catabay Caitlyn 
Published: May 2024

The digestive tract is central to the function of an animal since it assimilates nutrients from the diet. Digestion itself is a chemical process and digestive enzymes are the digestive catalysts. Thus, we measured amylase, maltase, N-acetyl-b-d-glucosaminidase, lipase, trypsin, aminopeptidase, and alkaline phosphatase activities along the digestive tract of the marine herbivorous fish, Cebidichthys violaceus. We did this for wild-caught individuals of this species, and compared those to individuals fed carnivore, omnivore, and herbivore diets in the laboratory for six months. In laboratory fish, the enzymatic activities were generally lower compared to wild-caught fish. In wild caught fish, a strong anterior-to-posterior gradient of amylase activity was observed along the gut and this pattern largely disappeared in the lab-fed fish. N-acetyl-β-D-glucosaminidase (NAGase), which breaks down chitin products, showed an increase in activity in the distal intestines of the lab-fed fish, which is not observed in wild fish. The NAGase activity of the herbivorous fishes correlate with the bacterial species Paroccus sp., which is a known NAGase producer, and one of the dominant microbes in the distal intestines of the lab-fed fish. The role of this enzyme, however, remains unclear since the lab diets did not contain large amounts of chitin. These enzymatic differences tell us how much fish can modify their enzymatic activity to align with their diet. In summary, the findings show that C. violaceous can endure different degrees of protein and carbohydrate levels, within limits. Their digestive system clearly changed in response to more protein in the diet, along with a microbiome that had more potential pathogens. Live algal diets would may be the most suitable for this herbivorous fish based on the totality of gathered data from the lab. American Physiological Society Fellowship UCI Microbiome Initiative Grant. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Mechanosensor channels of the lens and ciliary body: patch clamp studies
Authors: Ek-Vitorin Jose , Rahman Faiz Ur , Shahidullah Mohammad , Delamere Nicholas 
Published: May 2024

Epithelia from the lens and the ciliary body possess mechanosensors, including Piezo1 and transient receptor potential (TRP) channels, that may partake in the regulation of lens and aqueous humor volume. Although these mechanosensor channels commonly allow calcium entry, the outcomes of elevated intracellular calcium vary with the type of channel activated. For instance, separate activation of TRPV4 and TRPV1 increases Na-K-ATPase and Na/K/2Cl cotransporter activities, respectively. To further understand the role of mechanosensitivity in lens and ciliary body, we are currently using patch clamp techniques to characterize the response of primary cultured cells to chemical agonists and antagonists, as well as direct mechanical stimulation. Previously, we found that in mouse lens epithelial cells (mLEC), TRPV4 activation by agonist GSK1016790A (GSK) is followed by disappearance of a fast, transient K+-like outward current (Ipeak), decrease of a steady state outward current (Iss), fast depolarization of resting membrane potential (RMP) values from near -50 mV to near 0 mV, increase of Cx43 hemichannel-like events, and increase of overall membrane conductance ( gm) at holding potential (HP) = -50mV. More recently, we found that in mLEC, shear stress (streaming of external solution from a pipette tip over the cell membrane) reduced Ipeak but did not cause large RMP changes. Porcine non-pigmented epithelial cells (pNPE) in normal conditions display no Ipeak, small Iss, small RMP near -20 mV and spontaneous Cx43 hemichannel-like event activity. Nevertheless, GSK caused further depolarization of pNPE cells, and while no gm changes were seen when GSK was applied while holding cells at -50 mV, gm did increase when GSK exposure occurred during repeated ±80 mV pulses. Preliminary experiments show that activation of TRPM3 by its agonist pregnenolone causes a minimal hyperpolarization in mLEC. In comparison, in a line of human LEC (HLE B3) expressing TRPM3 channels, and which appear generally depolarized, pregnenolone caused a proportionally larger shift toward more negative RMP values; more intriguing, GSK has no measurable effect on the gm of HLE B3 cells. Taken together, and apart from considerations of cell- and species-specific differences, the data suggest that mechanosensor channels have different and/or opposite effects on the regulation of membrane ion channel activity, and thus on cell function. R01EY029171 and R01EY009532. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Time-Restricted Feeding Induces Beiging and Rejuvenates Adipose Tissue with Beneficial Effects on Cerebral Function in Old Mice
Authors: Reyff Zeke , Sanford Madison , Negri Sharon , Ballard Cade , Balasubramanian Priya , Tarantini Stefano 
Published: May 2024

Adipose tissue, traditionally viewed as purely an energy reserve, has recently been unveiled as a critical endocrine organ. Through the secretion of bioactive molecules known as adipokines, adipose tissue plays a role in inter-organ communication, most notably with the brain to maintain metabolic homeostasis and cognitive function. Aberrant adipokine secretion or signaling, often exacerbated with aging, has emerged as a defining characteristic of dysfunctional adipose tissue. This dysregulation can lead to inflammatory conditions, potentially disrupting neural homeostasis and heightening the vulnerability of older individuals to cognitive impairments. This study investigated the capacity of time-restricted feeding (TRF) to promote beiging (induction of brown adipocytes positive for uncoupling protein 1(UCP1) within white adipose tissue depots) in aged mice, exploring its potential role in modulating adipokine profiles, attenuating inflammation, and mitigating age-associated cognitive decline. To test this hypothesis, we collected adipose tissue samples from 24-month-old mice that underwent 6 months of TRF and compared their profiles to both young and age-matched controls on an unrestricted (ad-lib) diet. Immunohistochemical analyses of brown adipose tissue (BAT), subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT) revealed a marked reduction in pro-inflammatory markers CD80 and F4/80hi across all adipose tissues. Notably, a shift towards an anti-inflammatory state was indicated by a pronounced increase in CD163 staining in the SAT and VAT. Additionally, the increased expression of UCP1, especially in BAT and SAT, pointed towards an enhanced thermogenic capacity, suggesting a potential metabolic advantage. This was further reinforced by an increase in electron transport chain (ETC) activity in all adipose tissues. These findings have powerful implications given the established links between systemic inflammation, disrupted adipokine signaling, and neurodegenerative conditions. The alleviated adipose inflammatory profiles measured in TRF mice not only underscore its potential metabolic benefits but also highlight its possible role in safeguarding cognitive health, especially in an aging demographic. Currently serum studies and RNA sequencing are being conducted to look at altered transcript production and to investigate the role of adipokines on the brain health of the aged TRF mice. Such insights pave the way for future research exploring dietary strategies to combat age-related cognitive decline. Stephenson Cancer Center, National Institute on Aging R03 AG070479, American Heart Association. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.