Time Dependent Pathway Activation of Signalling Cascades in Rat Organs after Short-Term Hyperoxia

The frontier of precision medicine: application of single-cell multi-omics in preimplantation genetic diagnosis

The advent of single-cell multi-omics technologies has revolutionized the landscape of preimplantation genetic diagnosis (PGD), offering unprecedented insights into the genetic, transcriptomic, and proteomic profiles of individual cells in early-stage embryos. This breakthrough holds the promise of enhancing the accuracy, efficiency, and scope of PGD, thereby significantly improving outcomes in assisted reproductive technologies (ARTs) and genetic disease prevention. This review provides a comprehensive overview of the importance of PGD in the context of precision medicine and elucidates how single-cell multi-omics technologies have transformed this field. We begin with a brief history of PGD, highlighting its evolution and application in detecting genetic disorders and facilitating ART. Subsequently, we delve into the principles, methodologies, and applications of single-cell genomics, transcriptomics, and proteomics in PGD, emphasizing their role in improving diagnostic precision and efficiency. Furthermore, we review significant recent advances within this domain, including key experimental designs, findings, and their implications for PGD practices. The advantages and limitations of these studies are analyzed to assess their potential impact on the future development of PGD technologies. Looking forward, we discuss the emerging research directions and challenges, focusing on technological advancements, new application areas, and strategies to overcome existing limitations. In conclusion, this review underscores the pivotal role of single-cell multi-omics in PGD, highlighting its potential to drive the progress of precision medicine and personalized treatment strategies, thereby marking a new era in reproductive genetics and healthcare.

ROS-mediated MAPK activation aggravates hyperoxia-induced acute lung injury by promoting apoptosis of type II alveolar epithelial cells via the STAT3/miR-21-5p axis

Inhibition of type II alveolar epithelial (AE-II) cell apoptosis is a critical way to cure hyperoxia-induced acute lung injury (HALI). It has been reported that miR-21-5p could reduce H2O2-induced apoptosis in AE-II cells. However, the upstream molecular mechanism remains unclear. Herein, we established a cellular model of HALI by exposing AE-II cells to H2O2 treatment. It was shown that miR-21-5p alleviated H2O2-induced apoptosis in AE-II cells. ROS inhibition decreased apoptosis of H2O2-evoked AE-II cells via increasing miR-21-5p expression. In addition, ROS induced MAPK and STAT3 phosphorylation in H2O2-treated AE-II cells. MAPK inactivation reduces H2O2-triggered AE-II cell apoptosis. MAPK activation inhibits miR-21-5p expression by promoting STAT3 phosphorylation in H2O2-challenged AE-II cells. Furthermore, STAT3 activation eliminated MAPK deactivation-mediated inhibition on the apoptosis of AE-II cells under H2O2 condition. In conclusion, ROS-mediated MAPK activation promoted H2O2-triggered AE-II cell apoptosis by inhibiting miR-21-5p expression via STAT3 phosphorylation, providing novel targets for HALI treatment.

Effects of Hyperoxia and Hyperoxic Oscillations on the Proteome of Murine Lung Microvascular Endothelium

Patients presenting with insufficient tissue oxygenation and impaired lung function as in acute respiratory distress syndrome (ARDS) frequently require mechanical ventilation with supplemental oxygen. Despite the lung being used to experiencing the highest partial pressure of oxygen during healthy breathing, the organ is susceptible to oxygen-induced injury at supraphysiological concentrations. Hyperoxia-induced lung injury (HALI) has been regarded as a second hit to pre-existing lung injury and ventilator-induced lung injury (VILI) attributed to oxidative stress. The injured lung has a tendency to form atelectasis, a cyclic collapse and reopening of alveoli. The affected lung areas experience oxygen conditions that oscillate between hyperoxia and hypoxia rather than remaining in a constant hyperoxic state. Mechanisms of HALI have been investigated in many animal models previously. These studies provided insights into the effects of hyperoxia on the whole organism. However, cell type-specific responses have not been dissected in detail, but are necessary for a complete mechanistic understanding of ongoing pathological processes. In our study, we investigated the effects of constant and intermittent hyperoxia on the lung endothelium from a mouse by an in vitro proteomic approach. We demonstrate that these oxygen conditions have characteristic effects on the pulmonary endothelial proteome that underlie the physiological (patho)mechanisms.

Constitutive transgenic alpha-Klotho overexpression enhances resilience to and recovery from murine acute lung injury

AIMS

Normal lungs do not express alpha-Klotho (Klotho) protein but derive cytoprotection from circulating soluble Klotho. It is unclear whether chronic supranormal Klotho levels confer additional benefit. To address this, we tested the age-related effects of Klotho overexpression on acute lung injury (ALI) and recovery.

METHODS

Transgenic Klotho-overexpressing (Tg-Kl) and wild-type (WT) mice (2 and 6 months old) were exposed to hyperoxia (95% O₂; 72 h) then returned to normoxia (21% O₂; 24 h) (Hx-R). Control mice were kept in normoxia. Renal and serum Klotho, lung histology, and bronchoalveolar lavage fluid oxidative damage markers were assessed. Effects of hyperoxia were tested in human embryonic kidney cells stably expressing Klotho. A549 lung epithelial cells transfected with Klotho cDNA or vector were exposed to cigarette smoke; lactate dehydrogenase and double-strand DNA breaks were measured.

RESULTS

Serum Klotho decreased with age. Hyperoxia suppressed renal Klotho at both ages and serum Klotho at 2-months of age. Tg-Kl mice at both ages and 2-months-old WT mice survived Hx-R; 6-months-old Tg-Kl mice showed lower lung damage than age-matched WT mice. Hyperoxia directly inhibited Klotho expression and release in vitro; Klotho transfection attenuated cigarette smoke-induced cytotoxicity and DNA double-strand breaks in lung epithelial cells.

CONCLUSIONS

Young animals with chronic high baseline Klotho expression are more resistant to ALI. Chronic constitutive Klotho overexpression in older Tg-Kl animals attenuates hyperoxia-induced lung damage and improves survival and short-term recovery despite an acute reduction in serum Klotho level during injury. We conclude that chronic enhancement of Klotho expression increases resilience to ALI.

Benefits and harms of increased inspiratory oxygen concentrations

PURPOSE OF REVIEW

The topic of perioperative hyperoxia remains controversial, with valid arguments on both the 'pro' and 'con' side. On the 'pro' side, the prevention of surgical site infections was a strong argument, leading to the recommendation of the use of hyperoxia in the guidelines of the Center for Disease Control and the WHO. On the 'con' side, the pathophysiology of hyperoxia has increasingly been acknowledged, in particular the pulmonary side effects and aggravation of ischaemia/reperfusion injuries.

RECENT FINDINGS

Some 'pro' articles leading to the Center for Disease Control and WHO guidelines advocating perioperative hyperoxia have been retracted, and the recommendations were downgraded from 'strong' to 'conditional'. At the same time, evidence that supports a tailored, more restrictive use of oxygen, for example, in patients with myocardial infarction or following cardiac arrest, is accumulating.

SUMMARY

The change in recommendation exemplifies that despite much work performed on the field of hyperoxia recently, evidence on either side of the argument remains weak. Outcome-based research is needed for reaching a definite recommendation.

Proteomic Analysis of Morphologically Changed Tissues after Prolonged Dexamethasone Treatment

Prolonged dexamethasone (Dex) administration leads to serious adverse and decrease brain and heart size, muscular atrophy, hemorrhagic liver, and presence of kidney cysts. Herein, we used an untargeted proteomic approach using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for simultaneous identification of changes in proteomes of the major organs in Sprague–Dawley (SD rats post Dex treatment. The comparative and quantitative proteomic analysis of the brain, heart, muscle, liver, and kidney tissues revealed differential expression of proteins (n = 190, 193, 39, 230, and 53, respectively) between Dex-treated and control rats. Functional network analysis using ingenuity pathway analysis (IPA revealed significant differences in regulation of metabolic pathways within the morphologically changed organs that related to: (i) brain—cell morphology, nervous system development, and function and neurological disease; (ii) heart—cellular development, cellular function and maintenance, connective tissue development and function; (iii) skeletal muscle—nucleic acid metabolism, and small molecule biochemical pathways; (iv) liver—lipid metabolism, small molecular biochemistry, and nucleic acid metabolism; and (v) kidney—drug metabolism, organism injury and abnormalities, and renal damage. Our study provides a comprehensive description of the organ-specific proteomic profilesand differentially altered biochemical pathways, after prolonged Dex treatement to understand the molecular basis for development of side effects.