bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of OVLT or MnPO lesion on the gut microbiome
Authors: Pujagic Sejla , Pestana-Oliveira Nayara , Johnson Tim , Collister John 
Published: May 2024

Hypertension is a multifaceted condition affecting 700 million people worldwide, and despite decades of study, several aspects of its complex pathophysiology remain unclear. Changes in the gut microbiome have been associated with hypertension, though the cause and effect are not well defined. Historically, circumventricular organs in the brain, such as the organum vasculosum of the lamina terminalis (OVLT), and its central downstream nucleus the median preoptic nucleus (MnPO) have been shown to play a role in the pathogenesis of hypertension. Studies from our lab have demonstrated roles of both the OVLT and MnPO in the pathogenesis of angiotensin II mediated hypertension. Furthermore, we have previously reported that DOCA-salt treated OVLT lesioned rats had attenuated hypertension, and a gut microbial population more closely resembling normal controls, compared to sham lesioned rats. Lastly, we have recently shown the MnPO to be necessary in mediating DOCA-salt hypertension in the rat. Because data suggests changes in the gut microbiome occurred during the attenuated hypertensive response in lesioned animals, it is still unclear whether these changes occurred due to and shortly after the lesion, or subsequently during the hypertensive stimulus in lesioned animals. Therefore, the goal of this study was to further define the relationship between an OVLT or MnPO lesion and consequent changes in the gut microbiome without any hypertensive stimulus. Male Sprague Dawley rats underwent electrolytic lesion or sham operation using stereotaxic surgery with predetermined coordinates and settings. After 7 days, brain and regional gut tissues were harvested for analysis. Gut microbial genomic data from lesioned and sham rats were analyzed, and PCoA analysis showed statistically significant differences in microbiome composition between OVLT lesioned and sham rats in most gut regions. Generally, Shannon diversity analysis revealed sham rats had a more diverse population than OVLT lesioned rats, though both had a relatively similar spread of species abundance. Additionally, there was a common trend of higher relative abundance of Ligilactobacillus in lesioned rats for all four gut regions. In conclusion, the OVLT lesion itself has effects on the diversity of the gut microbiome, which suggest an OVLT-gut microbiome link that may contribute to attenuating hypertension. This study was supported by University of Minnesota Grant-In-Aid of Research, Artistry and Scholarship #546839 and a University of Minnesota Lillehei Heart Institute Collaborative Pilot 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.
Expression of the TGF-β Target Gene Mss51 Is Induced in Muscle From Tumor-Bearing Mice and Attenuated by Treatment With the AMPK Activator AICAR
Authors: Nickles P. Grace , Reid Olivia G. , Stark Isaac S. , Funk Zachary , Thomson David 
Published: May 2024

Cachexia is a severe complication of cancer characterized by skeletal muscle atrophy and loss of function and is associated with a poor prognosis. AMPK is a cellular energy sensor that is upregulated in cancer cachexia. AMPK activation is well-established in promoting catabolic cell signaling in skeletal muscle, partly through the induction of muscle-specific ubiquitin ligases MAFBx and MuRF-1 expression. Despite AMPK’s acute catabolic effects, chronic treatment with the AMPK-activating drug 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) has been reported to preserve muscle function and metabolism in various muscle-wasting conditions, including cancer cachexia. Elevated TGF-β during cancer cachexia is known to disrupt mitochondrial homeostasis and lead to mitochondrial dysfunction. Mss51 is a skeletal muscle-specific mitochondrial gene that is upregulated through TGF-β signaling. Although the role of Mss51 in skeletal muscle cancer cachexia has not been studied as of yet, its expression is associated with mitochondrial and metabolic impairment. Therefore, we hypothesized that Mss-51 expression would be elevated in cachexic skeletal muscle and attenuated by chronic AMPK activation. To test this, we inoculated mice (n=4) with either Lewis Lung Carcinoma (LLC) cells or PBS. Mice were injected daily with 350 mg/kg AICAR or an equivalent volume of saline beginning seven days after inoculation. Twenty-four days after inoculation, the mice were euthanized, and tissues were harvested and weighed. RNA was isolated from the gastrocnemius-plantaris-soleus complex and analyzed by RT-PCR for Mss51, MuRF-1, and MAFBx expression. Protein expression for hexokinase II (HKII) was measured by western blotting. AICAR treatment did not attenuate muscle atrophy in tumor-bearing mice. Compared to the control, Mss-51 was elevated in LLC mice treated with saline and decreased in LLC mice treated with AICAR, consistent with the known effects of AMPK in blocking TGF-β signaling. Similarly, MuRF-1 and MAFBx tended to be elevated in LLC-saline. Still, this increase was attenuated in LLC-AICAR mice, though we were likely underpowered to detect significance in this measure. In conclusion, based on previous work, the rise in Mss51 in tumor-bearing mice may contribute to mitochondrial and metabolic dysfunction in cancer cachexia. The prevention of this increase by AICAR suggests that AMPK may benefit dysfunctional metabolism in the cachexic muscle through inhibition of Mss51. Funding for these experiments was from a BYU Widtsoe 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.
Increased Oxygen Saturation Is Associated with Decreased Sympathetic Nervous System Activity in Individuals Given Bacteriotherapy at High Altitude
Authors: Cheng Hunter , Moya Esteban , Yu James J , Kaya Kiana , Ochoa Timothy , Simonson Tatum 
Published: May 2024

Exposure to low-oxygen conditions (hypoxia), as encountered at high altitudes and in some pathological conditions, results in the activation of various physiological stressors and acclimatization to hypoxia. Previous studies show that administration of a novel probiotic (SLAB51; O2BOOSTER; Hecto, Seoul, South Korea) improves oxygen saturation in severely hypoxemic COVID-19 patients and in healthy participants upon exposure to simulated and terrestrial hypobaric hypoxic. Whether SLAB51 impacts stress responses such as activation of the sympathetic nervous system during high-altitude exposure has not been evaluated. We hypothesized that SLAB51 treatment and the associated increase in oxygen saturation would reduce metrics of heart rate variability (HRV) at high altitude. Volunteers of Latino ancestry (n=17; eight women, nine men) were recruited and completed sea-level and high-altitude measurements (up to four days at the University of California White Mountain Barcroft Research Station, 12,470 ft / 3,801 m). Participants ingested either the SLAB51 probiotic or a placebo (randomized double-blind procedure) upon arrival and throughout their duration at altitude, and oxygen saturation (SpO2), electrocardiogram (EKG), mean arterial blood pressure (MABP), and heart rate (HR) measurements were collected during a fasted state each morning. We performed HRV analysis based on data from 10 minutes of resting EKG recordings, which included evaluations of low-frequency (LF) and high-frequency (HF) bands and their ratio (LF/HF) as an estimation of sympathetic activity. All values were compared between probiotic and placebo groups at high altitude (mean ± SEM). The two groups did not exhibit differences in LF/HF, MABP, and HR on any of the days spent at high altitude; however, during the first evening at high altitude when the treatment groups exhibited differences in SpO2 (separately reported), the probiotic group exhibited a non-significant trend of lower MABP relative to the placebo group (n = 5, 87.3 ± 2.5 and n = 4, 93.5 ± 3.5, respectively; p = 0.078). Additionally, higher SpO2 associated with lower MABP (R2 = 0.33) across all time points at high altitude in the probiotic group, but the opposite relationship was noted in the placebo group (R2 = 0.30). These data suggest potential differences in sympathetic nervous system activation in probiotic and placebo groups, a finding which warrants further investigation in a larger sample of individuals. SLAB51; O2BOOSTER; Hecto, Seoul, South Korea. 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.
The A986S calcium sensing receptor variant supports the adaptation of breast cancer cells to high calcium — a novel paradigm in breast cancer progression
Authors: SAKWE Nobelle , SAKWE Ngoc , Black Perrin , Ball Destiny , Wang Qingguo , Sakwe Amos 
Published: May 2024

Breast cancer and other solid tumors that metastasize to bone are frequently accompanied by a progressive increase in circulating calcium as the disease becomes more malignant. The increase in circulating calcium not only disrupts systemic calcium homeostasis but also alters the ability of cells to sense slight changes in extracellular Ca2+ via the ubiquitous calcium sensing receptor (CaSR). Of the CASR polymorphisms at rs1801725 (p.A986S), rs1801726 (p.Q1011E), and rs1042636 (p.R990G) in exon 7 of the receptor, previous studies have shown that only the A986S CaSR variant is associated with calcium in breast, prostate and skin cancers. In this study, we assessed if exon 7 inactivating A986S (AS-CaSR) and Q1011E (QE-CaSR) variants of the receptor influence the survival of breast tumor cells at higher Ca2+. We generated isogenic HEK293T and BT-549 cells expressing these CaSR variants and carried out bulk RNA sequencing of high Ca2+ adapted control and breast cancer cells. CaSR expression was detected by western blotting using anti-flag M2 (Sigma) antibody. By using phospho-ERK1/2 as the readout, the activation of AS-CaSR required higher concentrations of Ca2+ (EC50 ~5.28 mM) compared to the QE-CaSR (EC50 of ~3.81 mM) and the wild type (WT-CaSR; EC50 ~3.69 mM) receptor. When the CaSR variants transfected cells initially cultured at 7.5 mM for 6 days, and then sub-cultured in medium containing 7.5 to 20 mM Ca2+, the viability of empty vector control and WT-CaSR transfected cells strongly decreased at Ca2+ levels beyond 7.5 mM and these cells were mostly necrotic at ≥15 mM Ca2+. The QE-CaSR variant transfected cells on the other hand exhibited limited cell death beyond 10 mM Ca2+, while the surviving colonies of the AS-CaSR variant were viable at up to 15 mM Ca2+ with invasive tendencies. Analysis of differentially expressed genes in high Ca2+ adapted mesenchymal-like BT-549 and epithelial MDA-MB-468 breast cancer cells compared to MCF10A control cells revealed a small set of differentially expressed genes that were significantly associated with relapse free survival of basal-like breast cancer patients. Among these genes are ligands and negative regulators of the WNT/FZD pathway. Our data suggest that the A986S-CaSR variant with reduced sensitivity to Ca2+ supported adaptation of TNBC cells at high Ca2+, and that high Ca2+ adaptation of breast cancer cells may be mediated via a panel of high Ca2+ inducible genes with implications in bone metastasis. This study is supported by NIH SC1GM139814, T32AI007281, T32GM144927, T32HL007737; and the American Cancer Society. 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.
Sexual Dimorphism in Mitochondrial Metabolism and Insulin Sensitivity Is Controlled by HSP72-ERa Crosstalk
Authors: Morrow Noelle , Hevener Andrea 
Published: May 2024

HSP72 is highly induced during exercise, and muscle expression is reduced in obese and diabetic men. Muscle-specific HSP72 overexpression protects male mice against diet-induced obesity and insulin resistance. The current study objective was to determine the mechanisms by which HSP72 controls metabolic function and to ascertain whether these mechanisms are impacted by biological sex. We interrogated the impact of biological sex and estradiol action in the context of HSP72 loss and gain of expression in mice. HSP72 is a binding partner of the mitochondrial quality control protein Parkin. HSP72-KO led to metabolic dysfunction via impaired Parkin action, by promoting the retention of enlarged, fission incompetent mitochondria with reduced respiratory capacity. In contrast, female KOs remained lean and insulin sensitive with small spherical muscle mitochondria. Muscle estrogen receptor alpha transcript and protein (Esr1/ERa) was induced in female HSP72-KO vs. wildtype (WT), and this enhanced Parkin-DRP1-induced fatty acid oxidation and underpinned improvements in exercise capacity. The phenotype of female HSP72-KO mice recapitulates that of muscle-specific ESR1 overexpression animals. Because muscle ERa expression was identical between male genotypes, KO vs. WT, we treated male KO mice with 17β-estradiol and the treatment restored mitochondrial form/function as well as insulin sensitivity. In summary, biological sex is critical for understanding the impact of HSP72 in governing metabolic health and insulin sensitivity. National Institutes of Health DK060484 and P30DK063491. 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.
Sex-dependent polymorphism in urinary output is reversed upon deletion of exchange protein directly activated by cAMP (Epac)
Authors: Atamanchuk Anna , Pyrsev Kyrylo , Kordysh Mariya , Zaika Oleg , Pochynyuk Oleh 
Published: May 2024

It is well-described that there are notable sex-dependent differences in urinary production with females having a smaller volume and greater urinary concentrating ability. Apart from contribution of the androgenic inputs, the underlying signaling intermediates remain largely unexplored. We previously showed that exchange protein directly activated by cAMP (Epac) is a critical regulator of water-solute transport in the proximal tubule and collecting duct. Deletion of either Epac1 or Epac2 isoforms increases urinary output and Na+ excretion. Here, we used metabolic cage balance studies to test whether Epac signaling mediates sex-dependent differences in urinary production. We found that concomitant deletion of Epac1&2 moderately increases 24h urinary volume by 38% (from 1.82+/-0.13 to 2.52+/-0.21 ml) in males, but drastically augment urinary production in females by 320% (from 1.39+/-0.10 to 4.45+/-0.37 ml). This was associated with only a mild though significant reduction in urinary osmolarity in males by 35%, whereas urine osmolarity was markedly decreased from 2511+/-5 to 977+/-60 mOsm in females. Consistently, plasma osmolarity was not different in EpacWT versus Epac1&2−/− males, but became significantly more hypertonic in Epac1&2−/− females. We further determine the functional consequences of impaired Epac cascade on fluid reabsorption in the proximal tubule and collecting duct in males and females. Deletion of Epac1 and Epac2 decreases NHE-3 expression in the proximal tubule in an additive manner. In addition, Na+/H+-dependent recovery after acidification was drastically reduced in freshly isolated split-opened proximal tubules from Epac1&2−/− mice when compared to EpacWT. Interestingly, the reduction of NHE-3 expression was more pronounced in Epac1&2−/− females (by 89%) than in males (by 59%). Immunofluorescence confocal images revealed much more diffuse intracellular distribution of AQP2 water channel in Epac1&2−/− females when compared to males. Furthermore, osmotically-driven water influx was reduced in principal cells within split-opened collecting ducts of Epac1&2−/− females but not males, when compared to respective EpacWT. In summary, our results reveal a substantially greater role of Epac signaling in renal water handling in females than in males. Interestingly, Epac1&2 deletion leads to a reversed pattern of sexual dimorphism in urinary production with females excreting larger volumes of hypotonic urine than males. This research was supported by NIH-NIDDK DK117865, DK119170, AHA EIA35260097 (to O. Pochynyuk). 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.
Roles of mitofusin-2 in mouse neutrophil adhesion and development
Authors: Fan Zhichao , Pulikkot Sunitha , Liu Wei , Deng Qing 
Published: May 2024

Neutrophils play a critical role in inflammation and innate immunity. A crucial step in neutrophil recruitment is their adhesion to vascular endothelium. Previous research demonstrated the necessity of mitofusin-2 (MFN2) for integrin activation, adhesion, and the development of neutrophil-like HL60 cells. However, it remains unknown whether this holds true for primary neutrophils. Additionally, neutrophil adhesion is closely associated with their development, making it challenging to independently investigate the roles of MFN2 in regulating mouse neutrophil adhesion and development. In this study, we successfully addressed these challenges by utilizing two distinct conditional knockout mouse models. Our findings revealed that blood neutrophils from MFN2flox/flox LysM-cre mice exhibited approximately a 50% reduction in MFN2 expression. Remarkably, these MFN2 knockdown (KD) mice did not display any defects in neutrophil development. In contrast, blood neutrophils from MFN2flox/flox Vav-iCre mice showed a substantial (>90%) reduction in MFN2 expression. These MFN2 knockout mice exhibited a notable defect in the maturation of band cells into polymorphonuclear neutrophils. We further investigated the neutrophil adhesion using MFN2 knockdown mice and identified the neutrophil adhesion defect using microfluidics, the integrin activation defect using soluble ligand binding, and the Ca2+ flux defect using time-lapse flow cytometry. These findings provide valuable insights into the role of MFN2 in leukocyte adhesion and development and offer potential new perspectives for understanding and treating MFN2-deficiency-related diseases. This research was supported by grants from the National Institutes of Health, National Heart, Lung, and Blood Institute, USA (R01HL145454), National Institute of General Medical Sciences (R35GM119787), National Institute on Aging (P30AG024832), a Career re-entry fellowship from the American Association of Immunologists (G602182), and a startup fund from UConn Health. 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.
Beneficial Effect of Heat Treatment on the Exercise Pressor Reflex in Hindlimb Ischemia-Reperfusion: Potential Role of P2X3
Authors: Qin Lu , Li Qin , Li Jianhua 
Published: May 2024

PURPOSE: In peripheral artery disease (PAD), a greater blood pressure (BP) response during exercise causes cardiovascular and cerebrovascular risks. The exercise pressor reflex (EPR) is a key factor for why BP is exaggerated in PAD patients. Thus, we examined the effect of heat treatment (HT) with two temperature increments in skeletal muscle: 1.5 and 3oC on the EPR response following limb ischemia-reperfusion (IR) injury, one of the most common pathological conditions seen in PAD. In addition, the P2X3 (an ATP-sensitive receptor) in the muscle afferent dorsal root ganglion (DRG) was also evaluated. We hypothesized that IR upregulates the BP response to static muscle contraction and the protein expression of P2X3 in muscle afferent nerves. HT attenuates those exaggerated responses. METHODS: An experimental IR model was induced by 6 hours of ischemia followed by 18 hours of reperfusion in rats (IR rats). For HT groups, three HT sessions (muscle temperature increased by 1.5 or 3oC) for 30 mins/each time were applied. EPR response was evoked by static muscle contraction (30s). Protein expression of the P2X3 receptor in DRGs was examined. Data are presented as mean ± standard deviation. Results: The mean arterial pressure (MAP) response to the static muscle contraction was significantly exaggerated in rats of IR 18h (vs. Sham, P=0.018). With increasing Tm by 1.5°C, there was a promising trend that thus exaggerated BP response was attenuated (IR 18h + HT 1.5°C, n=5 vs. IR 18h rats, n=5, P=0.08). Meanwhile, the exaggerated BP response was significantly attenuated with the Tm increasing by 3°C (IR 18h + HT 3°C, n=5, vs. IR 18h rats, n=5, P=0.032). The expression of the P2X3 receptor was significantly enhanced in the DRGs of IR 18h rats (n=4, p<0.01 vs. sham, n=6). The upregulated P2X3 was suppressed in the DRGs of IR 18h rats +HT of 1.5°C (n=3, p<0.01 vs. IR 18h, n=4) and there was a promising trend that upregulated P2X3 was suppressed in the DRGs of IR 18h rats +HT of 3°C (n=3, P=0.079 vs. IR 18h, n=4). CONCLUSION: IR injury leads to upregulation of EPR response and this effect was attenuated by HT. The P2X3 signaling pathways are likely involved in the beneficial regulatory effect of HT on EPR in IR. Further data collection will be performed to test this conclusion. Supported by NIH R01 HL141198 & HL164571; AHA GRANT # 940567/Lu Qin/2022; and College of Medicine DOM Innovation and Inspiration Award. The authors sincerely thank Chunying Yang for the excellent technical assistance. 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.