Clinical science最新文献

The effect of high altitude (HA, altitude >2500 m) can trigger a maladaptive response in unacclimatized individuals, leading to various HA illnesses such as high altitude pulmonary edema (HAPE). The present study investigates circulating cell free (cf) DNA, a minimally invasive biomarker that can elicit a pro-inflammatory response. Our earlier study observed altered cfDNA fragment patterns in HAPE patients and the significant correlation of these patterns with peripheral oxygen saturation levels. However, the unclear release mechanisms of cfDNA in circulation limit its characterization and clinical utility. The present study not only observed a significant increase in cfDNA levels in HAPE patients (27.03 ± 1.37 ng/ml; n = 145) compared to healthy HA sojourners (controls, 14.57 ± 0.74 ng/ml; n = 65) and highlanders (HLs, 15.50 ± 0.8 ng/ml; n = 34) but also assayed the known cell death markers involved in cfDNA release at HA. The study found significantly elevated levels of the apoptotic marker, annexin A5, and secondary necrosis or late apoptotic marker, high mobility group box 1, in HAPE patients. In addition, we observed a higher oxidative DNA damage marker, 8-hydroxy-2'-deoxyguanosine, in HAPE compared with controls, suggestive of the role of oxidative DNA status in promoting the inflammatory potential of cfDNA fragments and their plausible role in manifesting HAPE pathophysiology. Extensive in vitro future assays can confirm the immunogenic role of cfDNA fragments that may act as a danger-associated molecular pattern and associate with markers of cellular stresses in HAPE.

Renin-expressing juxtaglomerular (JG) cells possess an intrinsic pressure-sensing mechanism(s) that regulates renin synthesis and release in response to changes in perfusion pressure. Although we recently described the structure of the nuclear mechanotransducer that controls renin transcription, the acute pressure-sensing mechanism that controls the rapid release of renin has not been identified. In JG cells there is an inverse relationship between intracellular calcium and renin release, the "calcium paradox". Since the discovery of Piezo2 as the "touch" receptors, there has been a significant interest in exploring whether they are also involved in other tissues beyond the skin. Given that Piezo receptors are permeable to calcium upon mechanical stimuli, it would be reasonable to hypothesize that Piezo2 controls renin synthesis and/or release in JG cells. To test this hypothesis, we used a variety of novel mouse models and JG cell-specific techniques to define whether Piezo2 controls renin expression and/or release in JG cells. Our in vivo data using constitutive and inducible Cre driver mouse lines and a variety of novel experimental approaches indicate that Piezo2 channels are not necessary for renin synthesis or release in JG cells during normal conditions or when homeostasis is threatened by hypotension, sodium depletion, or inverse changes in blood pressure. Furthermore, Piezo1 channels do not compensate for the lack of Piezo2 in JG cells. Efforts should be devoted to identifying the acute mechanosensory mechanisms controlling renin release.

Insulin secretion increases progressively during pregnancy to maintain normal maternal blood glucose levels. The placenta plays a crucial role in this process by releasing hormones and extracellular vesicles into the maternal circulation, which drive significant changes in pregnancy physiology. Placental extracellular vesicles, which are detectable in the plasma of pregnant women, have been shown to signal peripheral tissues and contribute to pregnancy-related conditions. While studies using murine models have demonstrated that extracellular vesicles can modulate insulin secretion in pancreatic islets, it remains unclear whether these effects translate to human biology. Understanding how placental signals enhance insulin synthesis and secretion from β cells could be pivotal in developing new therapies for diabetes. In our study, we isolated placental small extracellular vesicles from human placentae and utilised the human β cell line, EndoC-βH3, to investigate their effects on β-cell function in vitro. Our results indicate that human β cells internalise placental small extracellular vesicles, leading to enhanced insulin gene expression and increased insulin content within the β cells. Moreover, these vesicles up-regulated the expression of Annexin A1, a protein known to increase insulin content. This up-regulation of Annexin A1 holds promise as a potential mechanism by which placental small extracellular vesicles enhance insulin biosynthesis.

High-grade serous ovarian cancer (HG-SOC), accounting for 70-80% of ovarian cancer deaths, is characterized by a widespread and rapid metastatic nature, influenced by diverse cell types, cell-cell interactions, and acellular components of the tumour microenvironment (TME). Within this tumour type, autocrine and paracrine activation of the endothelin-1 receptors (ET-1R), expressed in tumour cells and stromal elements, drives metastatic progression. The lack of three-dimensional models that faithfully recapitulate the unique HG-SOC TME has been the bottleneck in performing drug screening for personalized medicine. Herein, we developed HG-SOC tumouroids by engineering a dense central artificial cancer mass (ACM) containing HG-SOC cells, nested within a compressed hydrogel recapitulating the stromal compartment comprising type I collagen, laminin, fibronectin, and stromal cells (fibroblasts and endothelial cells). ET-1-stimulated HG-SOC cells in the tumouroids showed an altered migration pattern and formed cellular aggregates, mimicking micrometastases that invaded the stroma. Compared with control cells, ET-1-stimulated tumouroids showed a higher number of invasive bodies, which were reduced by treatment with the dual ET-1 receptor (ET-1R) antagonist macitentan. In addition, ET-1 increased the size of the invading aggregates compared with control cells. This study establishes an experimental 3D multicellular model eligible for mechanical research, investigating the impact of matrix stiffness and TME interactions, which will aid drug screening to guide therapeutic decisions in HG-SOC patients.

 Mitochondrial dysfunction plays an important role in the development of podocyte injury in diabetic nephropathy (DN). Tunnelling nanotubes (TNTs) are long channels that connect cells and allow organelle exchange. Mesenchymal stromal cells (MSCs) can transfer mitochondria to other cells through the M-Sec-TNTs system. However, it remains unexplored whether MSCs can form heterotypic TNTs with podocytes, thereby enabling the replacement of diabetes-damaged mitochondria. In this study, we analysed TNT formation, mitochondrial transfer, and markers of cell injury in podocytes that were pre-exposed to diabetes-related insults and then co-cultured with diabetic or non-diabetic MSCs. Furthermore, to assess the in vivo relevance, we treated DN mice with exogenous MSCs, either expressing or lacking M-Sec, carrying fluorescent-tagged mitochondria. MSCs formed heterotypic TNTs with podocytes, allowing mitochondrial transfer, via a M-Sec-dependent mechanism. This ameliorated mitochondrial function, nephrin expression, and reduced apoptosis in recipient podocytes. However, MSCs isolated from diabetic mice failed to confer cytoprotection due to Miro-1 downregulation. In experimental DN, treatment with exogenous MSCs significantly improved DN, but no benefit was observed in mice treated with MSCs lacking M-Sec. Mitochondrial transfer from exogenous MSCs to podocytes occurred in vivo in a M-Sec-dependent manner. These findings demonstrate that the M-Sec-TNT-mediated transfer of mitochondria from healthy MSCs to diabetes-injured podocytes can ameliorate podocyte damage. Moreover, M-Sec expression in exogenous MSCs is essential for providing renoprotection in vivo in experimental DN.

Sickle Cell Disease (SCD) carries a significant risk for poor vascular health and vascular dysfunction. High levels of vascular reactive oxygen species (ROS) as well as elevated plasma endothelin-1 (ET-1), a potent vasoconstrictor with actions via the ETA receptor, are both common phenotypes in SCD. Alpha-1 adrenergic receptor activation is a major mediator of stress-induced vasoconstriction. However, the mechanism of the SCD enhanced vasoconstrictive response is unknown.  We hypothesized that SCD induces enhanced alpha-1 adrenergic mediated vasoconstriction through the ET-1/ETA receptor pathway in arterial tissues. Utilizing humanized SCD (HbSS) and genetic control (HbAA) mice, alpha-1a, but not alpha-1b or alpha-1d, receptor expression was significantly greater in aortic tissue from HbSS mice compared to HbAA mice. Significantly enhanced vasoconstriction in aortic and carotid arterial segments were observed from HbSS mice compared to HbAA mice. Treatment with ambrisentan, a selective ETA receptor antagonist, and a ROS scavenger normalized the aortic vasoconstrictive response in HbSS mice. In a randomized translational study, patients with SCD were treated with placebo or ambrisentan for 3 months, with the treatment group showing an increase in the percent brachial arterial diameter. Taken together, these data suggest that the ETA receptor pathway interaction with the adrenergic receptor pathway contributes to enhanced aortic vasoconstriction in SCD. Findings indicate the potential of ETA antagonism as a therapeutic avenue for improving vascular health in SCD.

Endothelin-1 (ET-1), the most potent vasoconstrictor identified to date, contributes to cerebrovascular dysfunction. ET-1 levels in postmortem brain specimens from individuals diagnosed with Alzheimer's disease (AD) and related dementias (ADRD) were shown to be related to cerebral hypoxia and disease severity. ET-1-mediated vascular dysfunction and ensuing cognitive deficits have also been reported in experimental models of AD and ADRD. Moreover, studies also showed that ET-1 secreted from brain microvascular endothelial cells (BMVECs) can affect neurovascular unit integrity in an autocrine and paracrine manner. Vascular contributions to cognitive impairment and dementia (VCID) is a leading ADRD cause known to be free of neuronal tau pathology, a hallmark of AD. However, a recent study reported cytotoxic hyperphosphorylated tau (p-tau) accumulation, which fails to bind or stabilize microtubules in BMVECs in VCID. Thus, the study aimed to determine the impact of ET-1 on tau pathology, microtubule organization, and barrier function in BMVECs. Cells were stimulated with 1 μM ET-1 for 24 h in the presence/absence of ETA (BQ123; 20 μM) or ETB (BQ788; 20 μM) receptor antagonists. Cell lysates were assayed for an array of phosphorylation site-specific antibodies and microtubule organization/stabilization markers. ET-1 stimulation increased p-tau Thr231 but decreased p-tau Ser199, Ser262, Ser396, and Ser214 levels only in the presence of ETA or ETB antagonism. ET-1 also impaired barrier function in the presence of ETA antagonism. These novel findings suggest that (1) dysregulation of endothelial tau phosphorylation may contribute to cerebral microvascular dysfunction and (2) the ET system may be an early intervention target to prevent hyperphosphorylated tau-mediated disruption of BMVEC barrier function.

The commentary discusses the regenerative capacity of the kidneys; recent studies reveal that renal cells can regenerate when exposed to certain conditions. A major focus is on scattered tubular-like cells (STCs), which can dedifferentiate and acquire progenitor-like properties in response to injury. These cells exhibit a glycolytic metabolism, making them resilient to hypoxic conditions and capable of repairing damaged renal tissues. Despite their potential, STCs are difficult to isolate and exist in small numbers. Here we highlight the need for more research into STC function, metabolic profiles, mechanisms limiting STC injury repair capacity, and methods of their pharmacological activation. Understanding these mechanisms could lead to novel therapies for kidney diseases.

Previous studies have shown beneficial effects of empagliflozin (Empa), a selective inhibitor of the sodium-glucose cotransporter 2 (SGLT2), on diabetes and cardiovascular outcomes in patients with diabetes. However, whether Empa could ameliorate diabetes mellitus (DM)-induced male spermatogenesis dysfunction remains unclear. Our study aimed to investigate the effect of Empa in the development of DM-induced male spermatogenesis dysfunction and to reveal the molecular mechanisms. DM mice were orally treated with Empa to investigate the effects of Empa on DM-induced male mice spermatogenesis dysfunction. We employed a cardiac-specific C1q/tumor necrosis factor-related protein 9 (CTRP9)-deficient mouse model and a cardiac-specific CTRP9 overexpression mouse model to investigate its role in the protection of Empa against diabetes-induced male subfertility. We found that Empa treatment could improve DM-induced male mice subfertility. Interestingly, we discovered that cardiac-derived CTRP9 was decreased in DM mice and this decrease was prevented by Empa treatment. A CTRP9 blocking antibody or cardiac-specific depletion of CTRP9 abolished the protection of Empa on DM-induced male subfertility. Cardiac-specific CTRP9 overexpression ameliorated DM-induced male subfertility. Mechanistically, we identified that cardiac-derived CTRP9 increased steroidogenesis in mice with diabetes in a PKA-dependent manner. We also provided direct evidence that activation of AMP activated protein kinase α (AMPKα)/nuclear factor (erythroid-derived 2)-like 2 (Nrf2) signalling pathway by CTRP9 was responsible for the attenuation of ferroptosis in Leydig cells. In conclusions, we supposed that Empa was a potential therapeutic agent against DM-induced male mice spermatogenesis dysfunction.