Estrogen receptor (ESR1 and ESR2)-mediated activation of eNOS-NO-cGMP pathway facilitates high altitude acclimatization

The exploration of the effect and mechanism of Shengxian decoction inhibiting acute high-altitude myocardial injury

BACKGROUND

The heart is the most vulnerable organ to acute hypobaric hypoxia exposure, acute high-altitude myocardial injury (AHMI) typically occurs in individuals who rapidly ascend from lowland areas to high-altitude regions. Effective intervention strategies for AHMI have garnered significant attention, with Shengxian decoction (SXD) emerging as a potential therapeutic agent; however, the underlying mechanism remains unclear.

PURPOSE

The objective of this study was to explore the effective components, potential targets and regulatory mechanisms of SXD in improving AHMI.

STUDY DESIGN

This study innovatively employed the combined strategy including network pharmacology, transcriptomics, proteomics, molecular docking, and molecular biology to analyze the targets and mechanism pathways of SXD for improving AHMI. Ultra-high-performance liquid chromatography/Q Exactive HFX mass spectrometry (UHPLC-QE-MS) and network pharmacology were adopted to identify active ingredients and analyze their functions. On this basis, transcriptomics and proteomics technologies were integrated to further investigate and validate the mechanisms at both gene and protein levels. Additionally, a herbs-components-targets-pathways (HCTP) network was generated for exploration and analysis. Molecular docking was utilized for an in-depth examination of the binding activity between screened components and targets. Finally, molecular biology techniques were applied to re-confirm the targets and mechanisms involved.

RESULTS

SXD effectively reduced heart's abnormal electrical activity, inhibited the release of various myocardial enzymes, troponins and inflammatory factors into the blood. Network pharmacology, transcriptomics, proteomics revealed that inflammatory response was important for the effects of SXD in AHMI. The combined analysis of network pharmacology, transcriptomics, proteomics constructed the HCTP network encompassing 5 herbs, 13 active ingredients, 146 targets and 20 signaling pathways to elucidate the mechanism by which SXD exerts its effects on AHMI, further analysis suggested that SXD regulated IL-17, MAPK/ERK, and Ras signaling pathways to alleviate AHMI.

CONCLUSION

The positive effect of SXD on AHMI was achieved through the regulation of inflammation-related pathways (IL-17, MAPK/ERK, and Ras signaling pathways), the inhibition of inflammatory factors releases and the modulation of the inflammatory response.

Maternal exposure to fullerenols impairs placental development in mice by inhibiting estriol synthesis and reducing ERα

Fullerenols, a water-soluble polyhydroxy derivative of fullerene, hold promise in medical and materials science due to their unique properties. However, concerns about their potential embryotoxicity remain. Using a pregnancy mouse model and metabolomics analysis, our findings reveal that fullerenols exposure during pregnancy not only significantly reduced mice placental weight and villi thickness, but also altered the classes and concentrations of metabolites in the mouse placenta. Furthermore, we found that fullerenols exposure reduced the levels of CYP3A4, ERα and estriol (E3), while increasing the levels of estradiol (E2) and oxidative stress both in mouse placenta and placental trophoblast cells, and exogenous supplementation with E3 and ER agonists was effective in restoring these changes in vitro. Moreover, CYP3A4 inhibition was effective in decreasing intracellular E3 levels, whereas overexpression of CYP3A4 resisted the fullerenols-induced decrease in E3 expression Additionally, we synthesized glutathione-modified fullerenols (C60-(OH)n-GSH), which demonstrated improved biocompatibility and reduced embryotoxicity by enhancing intracellular glutathione levels and mitigating oxidative stress. In summary, our results demonstrated that fullerenols exposure decreased E3 synthesis by inhibiting CYP3A4 and exacerbated oxidative stress through downregulation of estrogen receptor activation and decreased glutathione levels. These findings highlight the risks of fullerenols exposure during pregnancy and offer strategies for safer nanomaterial development.

Genomic Variation, Population History, and Long-Term Genetic Adaptation to High Altitudes in Tibetan Partridge (Perdix hodgsoniae)

Species residing across elevational gradients display adaptations in response to environmental changes such as oxygen availability, ultraviolet radiation, and temperature. Here, we study genomic variation, gene expression, and long-term adaptation in Tibetan Partridge (Perdix hodgsoniae) populations residing across the elevational gradient of the Tibetan Plateau. We generated a high-quality draft genome and used it to carry out downstream population genomic and transcriptomic analysis. The P. hodgsoniae populations residing across various elevations were genetically distinct, and their phylogenetic clustering was consistent with their geographic distribution. We identified possible evidence of gene flow between populations residing in <3,000 and >4,200 m elevation that is consistent with known habitat expansion of high-altitude populations of P. hodgsoniae to a lower elevation. We identified a 60 kb haplotype encompassing the Estrogen Receptor 1 (ESR1) gene, showing strong genetic divergence between populations of P. hodgsoniae. We identified six single nucleotide polymorphisms within the ESR1 gene fixed for derived alleles in high-altitude populations that are strongly conserved across vertebrates. We also compared blood transcriptome profiles and identified differentially expressed genes (such as GAPDH, LDHA, and ALDOC) that correlated with differences in altitude among populations of P. hodgsoniae. These candidate genes from population genomics and transcriptomics analysis were enriched for neutrophil degranulation and glycolysis pathways, which are known to respond to hypoxia and hence may contribute to long-term adaptation to high altitudes in P. hodgsoniae. Our results highlight Tibetan Partridges as a useful model to study molecular mechanisms underlying long-term adaptation to high altitudes.

Male-biased association of endothelial nitric oxide synthase Asp298Glu substitution (NOS3-c.894G/T) with asthma risk and severity

OBJECTIVE

The nitric-oxide pathway plays a crucial role in the pathogeneses of asthma and NOS3-encoded endothelial nitric oxide synthase is one of the main components of the pathway. Variants of NOS3 are known to contribute to asthma development and pathophysiology.

METHODS

We investigated the association of NOS3-c.894G/T (rs1799983) with asthma risk and severity by studying frequencies of its genotypes and alleles in 555 asthmatics (93 intermittent, 240 mild, 158 moderate, and 64 severe asthma cases) and 351 control participants using the PCR-FRLP method, logistic regression analysis and generalized ordered logit estimates.

RESULTS

GT genotype (OR_adj: 1.39; CI: 1.04-1.85; p = 0.026), dominant model GT + TT (OR_adj: 1.41; CI: 1.07-1.87; p = 0.015), and T allele (OR_adj: 1.32; CI: 1.05-1.67; p = 0.018) was associated with increased ORs in asthmatics. Also, the frequency of GT + TT (OR_adj: 1.55; CI: 1.01-2.38; p = 0.044) was significantly higher in males. Furthermore, GT genotype (OR_adj: 1.39; CI: 1.04-1.85; p = 0.024), GT + TT (OR_adj: 1.42; CI: 1.07-1.87; p = 0.014), and T allele (OR_adj: 1.32; CI: 1.05-1.66; p = 0.018) in total population and GT + TT (OR_adj: 1.56; CI: 1.02-2.37; p = 0.04) in males were significantly associated with increased risk of severe, moderate, mild, intermittent asthma vs. controls. Also, GT genotype (OR_adj: 1.39; CI: 1.02-1.91; p = 0.039) was significantly more frequent in severe, moderate grades vs. lower severity grades in the total population. Frequencies of GT genotype (OR_adj: 1.77; CI: 1.05-3.00; p = 0.032) and GT + TT (OR_adj: 1.74; CI: 1.04-2.90; p = 0.036) in total population and GT genotype (OR_adj: 2.40; CI: 1.16-4.97; p = 0.018) and GT + TT (OR_adj: 2.30; CI: 1.12-4.74; p = 0.023) in male subpopulation were significantly higher in severe cases compared to lower grades.

CONCLUSIONS

NOS3-c.894G/T may be associated with asthma risk and its severer grades, with greater effects in men.

The Oxygen Cascade from Atmosphere to Mitochondria as a Tool to Understand the (Mal)adaptation to Hypoxia

Hypoxia is a life-threatening challenge for about 1% of the world population, as well as a contributor to high morbidity and mortality scores in patients affected by various cardiopulmonary, hematological, and circulatory diseases. However, the adaptation to hypoxia represents a failure for a relevant portion of the cases as the pathways of potential adaptation often conflict with well-being and generate diseases that in certain areas of the world still afflict up to one-third of the populations living at altitude. To help understand the mechanisms of adaptation and maladaptation, this review examines the various steps of the oxygen cascade from the atmosphere to the mitochondria distinguishing the patterns related to physiological (i.e., due to altitude) and pathological (i.e., due to a pre-existing disease) hypoxia. The aim is to assess the ability of humans to adapt to hypoxia in a multidisciplinary approach that correlates the function of genes, molecules, and cells with the physiologic and pathological outcomes. We conclude that, in most cases, it is not hypoxia by itself that generates diseases, but rather the attempts to adapt to the hypoxia condition. This underlies the paradigm shift that when adaptation to hypoxia becomes excessive, it translates into maladaptation.

The role of sex and ovarian hormones in hippocampal damage and cognitive deficits induced by chronic exposure to hypobaric hypoxia

Purpose

This study aims to investigate the role of sex and ovarian hormones in hippocampal damage and cognitive deficits and behavioral dysfunction in rats induced by chronic exposure to hypobaric hypoxia.

Methods

Six-week-old male and female SD rats were housed for 3 months either in a real altitude (4,250 m) environment as the model of chronic hypobaric-hypoxia (CHH) or in a plain as controls. The animal behavioral and hippocampal neurons at subcellular, molecular, and ultrastructural levels were characterized after CHH exposure.

Results

After 3 months of CHH exposure, (1) male CHH rats’ serum testosterone level was lower than male controls’ whereas female CHH rats’ serum estradiol level was higher than female controls’; (2) Morris water maze test finds that male rats showed more learning and spatial memory deficits than female rats; (3) male rats showed more severe hippocampal damage, hippocampal inflammation, oxidative stress and decreased hippocampal integrity (neurogenesis and dendritic spine density) than female rats; (4) Western blot analysis shows that, compared with the male control group, in male CHH group’s hippocampus, expression of nNOS, HO-1, and Bax protein increased whereas that of Bcl-2 protein decreased; (5) Expression of PON2 protein in male rats (CHH and controls) was lower than female rats (CHH and controls). In addition, CHH exposure decreased the expression of PON2 protein in both male and female rats; (6) qPCR analysis reveals that CHH exposure reduced the gene expression of N-methyl-D-aspartate receptor NR2A and NR2B subunits in male rats’ hippocampus. In addition, compared with the sham CHH group, the expression level of PON2 protein decreased in the OVX-CHH group’s hippocampus whereas oxidative stress, neuroinflammation, and degeneration of hippocampal neurons increased in the OVX-CHH group’s hippocampus.

Conclusion

After CHH exposure, male rats were significantly more likely than female rats to develop hippocampal damage, hippocampal neuroinflammation, and cognitive decline and deficits, suggesting that sex and ovarian hormones were significantly involved in regulating the rats’ susceptibility to CHH exposure-induced hippocampal damage.

TMT-Based Plasma Proteomics Reveals Dyslipidemia Among Lowlanders During Prolonged Stay at High Altitudes

Acute exposure to high altitude perturbs physiological parameters and induces an array of molecular changes in healthy lowlanders. However, activation of compensatory mechanisms and biological processes facilitates high altitude acclimatization. A large number of lowlanders stay at high altitude regions from weeks to months for work and professional commitments, and thus are vulnerable to altitude-associated disorders. Despite this, there is a scarcity of information for molecular changes associated with long-term stay at high altitudes. In the present study, we evaluated oxygen saturation (SpO₂), heart rate (HR), and systolic and diastolic blood pressure (SBP and DBP) of lowlanders after short- (7 days, HA-D7) and long-term (3 months, HA-D150) stay at high altitudes, and used TMT-based proteomics studies to decipher plasma proteome alterations. We observed improvements in SpO₂ levels after prolonged stay, while HR, SBP, and DBP remained elevated as compared with short-term stay. Plasma proteomics studies revealed higher levels of apolipoproteins APOB, APOCI, APOCIII, APOE, and APOL, and carbonic anhydrases (CA1 and CA2) during hypoxia exposure. Biological network analysis also identified profound alterations in lipoprotein-associated pathways like plasma lipoprotein assembly, VLDL clearance, chylomicron assembly, chylomicron remodeling, plasma lipoprotein clearance, and chylomicron clearance. In corroboration, lipid profiling revealed higher levels of total cholesterol (TC), triglycerides (TGs), low-density lipoprotein (LDL) for HA-D150 whereas high density lipoproteins (HDL) levels were lower as compared with HA-D7 and sea-level indicating dyslipidemia. We also observed higher levels of proinflammatory cytokines IL-6, TNFα, and CRP for HA-D150 along with oxidized LDL (oxLDL), suggesting vascular inflammation and proartherogenic propensity. These results demonstrate that long-term stay at high altitudes exacerbates dyslipidemia and associated disorders.

Protective Effects of Estrogen on Cardiovascular Disease Mediated by Oxidative Stress

Perimenopause is an important stage of female senescence. Epidemiological investigation has shown that the incidence of cardiovascular disease in premenopausal women is lower than that in men, and the incidence of cardiovascular disease in postmenopausal women is significantly higher than that in men. This phenomenon reveals that estrogen has a definite protective effect on the cardiovascular system. In the cardiovascular system, oxidative stress is considered important in the pathogenesis of atherosclerosis, myocardial dysfunction, cardiac hypertrophy, heart failure, and myocardial ischemia. From the perspective of oxidative stress, estrogen plays a regulatory role in the cardiovascular system through the estrogen receptor, providing strategies for the treatment of menopausal women with cardiovascular diseases.

Association Between 17β-Estradiol Receptors and Nitric Oxide Signaling Augments High-Altitude Adaptation of Ladakhi Highlanders

Pooja, Vandana Sharma, Manish Sharma, Rajeev Varshney, Bhuvnesh Kumar, and Niroj Kumar Sethy. Association between 17β-estradiol receptors and nitric oxide signaling augments high-altitude adaptation of Ladakhi highlanders. High Alt Med Biol. 22: 174-183, 2021. Background: Genomic studies have identified positive natural selection of plasma membrane estrogen receptor signaling pathway for Himalayan highlanders. We sought to investigate significance of this pathway for high-altitude adaptation by studying Ladakhi highlanders. Materials and Methods: We recruited 25 healthy Ladakhi males (age range: 19-37, height: 164 ± 6 cm, and weight 59 ± 4 kg) at Leh (altitude 3,520 m) and age matched sea level volunteers at Delhi (altitude 215 m), India. We evaluated circulatory levels of 17β-estradiol (E2) and testosterone (T) and levels of E2 biosynthesis pathway proteins. In addition, we analyzed mRNA levels of E2 pathway genes and their association with nitric oxide (NO) availability. Results: We observed higher circulatory E2 and lower testosterone (T) in Ladakhi highlanders compared to lowlanders. Studying E2 pathway genes, we identified higher transcript levels of E2 receptors ESR1 (2.02-fold) and ESR2 (3.87-fold) in Ladakhi highlanders. Higher NOS3 mRNA, plasma level of endothelial NO synthase (eNOS), p-eNOS ^Ser1177, NOx (nitrate and nitrite), and cGMP were observed for Ladakhi highlanders. In addition, we observed a positive correlation between E2 with plasma NOx (r = 0.52, p = 0.002) and cGMP (r = 0.72, p = 0.007) for Ladakhi highlanders. Conclusion: Our results demonstrate higher circulatory E2 and lower T levels in Ladakhi highlanders. Higher levels of E2 and its receptors (ESR1 and ESR2) are positively associated with observed higher levels of eNOS signaling pathway metabolites. These results highlight the functional importance of E2 and its receptors for Himalayan pattern of high-altitude adaptation.