Isolating pulmonary microvascular endothelial cells ex vivo: Implications for pulmonary arterial hypertension, and a caution on the use of commercial biomaterials

Erythrophagocytosis-induced ferroptosis contributes to pulmonary microvascular thrombosis and thrombotic vascular remodeling in pulmonary arterial hypertension

BACKGROUND

Whether primary or just as a complication from the progression of pulmonary arterial hypertension (PAH), thrombosis seems to be an important player in this condition. The crosstalk between red blood cells (RBCs) and pulmonary microvascular endothelial cells (PMVECs) and their role in PAH remain undefined.

OBJECTIVES

The goals of this study were to assess the role of RBC-PMVEC interaction in microvascular thrombosis and thrombotic vascular remodeling under hypoxic conditions.

METHODS

We established an in vitro hypoxic coincubation model of RBC and PMVEC as well as a hypoxic mouse model. We investigated erythrophagocytosis (EP), ferroptosis, thrombosis tendency, and pulmonary hemodynamics in experimental PAH.

RESULTS

Increased EP in PMVEC triggered ferroptosis, enhanced procoagulant activity, and exacerbated vessel remodeling under hypoxic conditions. In the PAH mouse model induced by chronic hypoxia, EP-induced ferroptosis followed by upregulated TMEM16F led to a high tendency of thrombus formation and thrombotic vascular remodeling. Inhibition of ferroptosis or silencing of TMEM16F could alleviate hypercoagulable phenotype, reverse right ventricular systolic pressure, right ventricular hypertrophy index, and remodeling of pulmonary vessels.

CONCLUSION

These results illustrate the pathogenic RBC-PMVEC interactions in PAH. Inhibition EP, ferroptosis, or TMEM16F could be a novel therapeutic target to prevent PAH development and thrombotic complications.

Temperature adaptation patterns in Chinese cattle revealed by TRPM2 gene mutation analysis

Cattle are sensitive to temperature fluctuations but adapt well to inclement weather conditions. When environmental temperatures exceed specific thresholds, heat stress becomes a critical concern for cattle. The TRPM2 gene, which resides on cattle chromosome 1 encodes a TRP channel protein, holding a unique capacity to sense temperature changes and facilitate rapid response to avoid heat stress. Here, we utilized the Bovine Genome Variation Database (BGVD) (http://animal.omics.pro/code/index.php/BosVar), and identified a missense mutation site, c.805A > G: p. Met269Val (rs527146862), within the TRPM2 gene. To elucidate the functional assessment of this mutation in temperature adaptation attributes of Chinese cattle, we genotyped 407 samples from 20 distinct breeds representing diverse climatic zones across China. The association analysis incorporates three temperature parameters and revealed compelling insights in terms of allele frequency. Interestingly, the prevalence of the wild-type allele A was notably higher among northern cattle breeds and this trend diminished gradually as observed in southern cattle populations. Conversely, the mutant-type allele G demonstrated a contrasting trend. Moreover, southern cattle exhibited markedly higher frequencies of GG and GA genotypes (P < 0.01). The presence of heterozygous and homozygous mutations appears to confer an enhanced capacity for adaptation to elevated temperatures. These results provide unequivocal correlation evidence between TRPM2 genotypes (AA, GA, GG) and environmental temperature parameters and comprehend the genetic mechanisms governing temperature adaptation in cattle. This provides valuable insights for strategic breed selection across diverse climatic regions, thereby aiding livestock production amid evolving climate challenges.

Proline and glucose metabolic reprogramming supports vascular endothelial and medial biomass in pulmonary arterial hypertension

In pulmonary arterial hypertension (PAH), inflammation promotes a fibroproliferative pulmonary vasculopathy. Reductionist studies emphasizing single biochemical reactions suggest a shift toward glycolytic metabolism in PAH; however, key questions remain regarding the metabolic profile of specific cell types within PAH vascular lesions in vivo. We used RNA-Seq to profile the transcriptome of pulmonary artery endothelial cells (PAECs) freshly isolated from an inflammatory vascular injury model of PAH ex vivo, and these data were integrated with information from human gene ontology pathways. Network medicine was then used to map all aa and glucose pathways to the consolidated human interactome, which includes data on 233,957 physical protein-protein interactions. Glucose and proline pathways were significantly close to the human PAH disease module, suggesting that these pathways are functionally relevant to PAH pathobiology. To test this observation in vivo, we used multi-isotope imaging mass spectrometry to map and quantify utilization of glucose and proline in the PAH pulmonary vasculature at subcellular resolution. Our findings suggest that elevated glucose and proline avidity underlie increased biomass in PAECs and the media of fibrosed PAH pulmonary arterioles. Overall, these data show that anabolic utilization of glucose and proline are fundamental to the vascular pathology of PAH.

NORAD modulates miR-30c-5p-LDHA to protect lung endothelial cells damage

Acute lung injury (ALI) is a devastating human malignancy characterized by excessively uncontrolled inflammation and lung endothelial dysfunction. Non-coding RNAs play essential roles in endothelial protections during the pathological processes of ALI. The precise functions and molecular mechanisms of the lncRNA-NORAD-mediated endothelial protection remain obscure. This study reports NORAD was significantly induced in human pulmonary microvascular endothelial cells (HPMECs) under lipopolysaccharide (LPS) treatment. Silencing NORAD effectively protected HPMECs against the LPS-induced cell dysfunction. In addition, RNA pull-down and luciferase assay validated that NORAD sponged miR-30c-5p, which showed reverse functions of NORAD in the LPS-induced cell injury of HPMECs. Furthermore, the glucose metabolism of HPMECs was significantly elevated under LPS stimulation which promoted the glucose consumption and extracellular acidification rate (ECAR) of HPMECs. Inhibiting NORAD or overexpressing miR-30c-5p suppressed glucose metabolism in HPMECs, leading to protective effects on HPMECs under LPS stimulation. The glycolysis key enzyme, lactate dehydrogenase-A (LDHA), was subsequently identified as a direct target of miR-30c-5p. Finally, recovery of miR-30c-5p in NORAD-overexpressing HPMECs effectively overrode the NORAD-promoted glycolysis and impaired endothelial dysfunction under LPS stimulation by targeting LDHA. Summarily, we demonstrated a NORAD-miR-30c-5p-LDHA-glycolysis axis in the LPS-induced HPMECs dysfunction in vitro and in vivo, contributing to the development of anti-ALI therapeutic approaches.

Morroniside enhances angiogenesis and improves cardiac function following acute myocardial infarction in rats

Angiogenesis is critical for re-establishing blood supply to the ischemic myocardium after acute myocardial infarction (AMI). This study aimed to investigate the effects of morroniside on angiogenesis after AMI and explored associated proangiogenic mechanisms. A rat model of AMI was established by ligation of the left anterior descending coronary artery followed by administration of three doses of morroniside. Immunofluorescence staining was performed to identify newly generated endothelial cells and arterioles. The protein expression levels associated with angiogenesis were examined by western blots. Echocardiography was used to examine cardiac function. Our data revealed that morroniside promoted angiogenesis and improved cardiac function in rats with AMI. The proangiogenic effect of morroniside might be mediated by the VEGFA/VEGF receptor 2 signaling pathway.

Circulating NEDD9 is increased in pulmonary arterial hypertension: A multicenter, retrospective analysis

BACKGROUND

Pulmonary arterial hypertension (PAH) is a highly morbid disease characterized by elevated pulmonary vascular resistance (PVR) and pathogenic right ventricular remodeling. Endothelial expression of the prometastatic protein NEDD9 is increased in fibrotic PAH arterioles, and NEDD9 inhibition decreases PVR in experimental PAH. We hypothesized that circulating NEDD9 is increased in PAH and informs the clinical profile of patients.

METHODS

Clinical data and plasma samples were analyzed retrospectively for 242 patients from 5 referral centers (2010-2017): PAH (n = 139; female 82%, 58 [48-67] years), non-PAH pulmonary hypertension (PH) (n = 54; female 56%, 63.4 ± 12.2 years), and dyspnea non-PH controls (n = 36; female 75%, 54.2 ± 14.0 years).

RESULTS

Compared with controls, NEDD9 was increased in PAH by 1.82-fold (p < 0.0001). Elevated NEDD9 correlated with PVR in idiopathic PAH (ρ = 0.42, p < 0.0001, n = 54), connective tissue disease (CTD)-PAH (ρ = 0.53, p < 0.0001, n = 53), and congenital heart disease-PAH (ρ = 0.68, p < 0.0001, n = 10). In CTD-PAH, NEDD9 correlated with 6-minute walk distance (ρ = -0.35, p = 0.028, n = 39). In contrast to the PAH biomarker N-terminal pro-brain natriuretic peptide (n = 38), NEDD9 correlated inversely with exercise pulmonary artery wedge pressure and more strongly with right ventricular ejection fraction (ρ = -0.41, p = 0.006, n = 45) in a mixed population. The adjusted hazard ratio for lung transplant-free survival was 1.12 (95% confidence interval [CI], 1.02-1.22, p = 0.01) and 1.75 (95% CI, 1.12-2.73, p = 0.01) per 1 ng/ml and 5 ng/ml increase in plasma NEDD9, respectively, by Cox proportional hazard model.

CONCLUSIONS

In PAH, plasma NEDD9 is increased and associates with key prognostic variables. Prospective studies that include hard end points are warranted to validate NEDD9 as a novel PAH biomarker.

Pericytes in Cerebrovascular Diseases: An Emerging Therapeutic Target

Pericytes are functional components of the neurovascular unit (NVU) that are located around the blood vessels, and their roles in the regulation of cerebral health and diseases has been reported. Currently, the potential properties of pericytes as emerging therapeutic targets for cerebrovascular diseases have attracted considerable attention. Nonetheless, few reviews have comprehensively discussed pericytes and their roles in cerebrovascular diseases. Therefore, in this review, we not only summarized and described the basic characteristics of pericytes but also focused on clarifying the new understanding about the roles of pericytes in the pathogenesis of cerebrovascular diseases, including white matter injury (WMI), hypoxic-ischemic brain damage, depression, neovascular insufficiency disease, and Alzheimer's disease (AD). Furthermore, we summarized the current therapeutic strategies targeting pericytes for cerebrovascular diseases. Collectively, this review is aimed at providing a comprehensive understanding of pericytes and new insights about the use of pericytes as novel therapeutic targets for cerebrovascular diseases.