Hypoxia Upregulates NOTCH3 Signaling Pathway to Promote Endothelial-Mesenchymal Transition in Pulmonary Artery Endothelial Cells

Mechanism of pulmonary arterial vascular cell dysfunction in pulmonary hypertension in broiler chickens

Broiler ascites syndrome is a common and complex disease in broiler farming, which severely impacts broiler growth performance and health and brings huge economic losses to the breeding industry. Hypoxia has been shown to be an important cause of this disease. Prolonged exposure of broiler chickens to a hypoxic environment induces pulmonary vasoconstriction, which leads to an increase in pulmonary artery pressure, triggering pulmonary artery remodelling and compensatory right ventricular hypertrophy, and ultimately ascites. Pulmonary artery remodelling is a process in which the vascular wall tissue structure and function undergo pathological changes after the pulmonary artery is stimulated by various injuries or hypoxia, including endothelial dysfunction, abnormal proliferation of pulmonary artery smooth muscle cells, vascular fibrosis, etc. When these cells are damaged or stimulated, they may undergo programmed cell death, an orderly and regulated mode of cell death that is important for maintaining the stability of the body's internal environment. It has been demonstrated that death modes such as apoptosis and autophagy are involved in the pathophysiologic process of pulmonary hypertension, but their specific molecular mechanisms are still unclear. In this review, we first describe the pathogenesis of broiler ascites, then describe the specific mechanism of dysfunction of pulmonary artery vascular cells in broiler ascites syndrome, and finally elaborate the progression of different programmed cell death in broiler pulmonary hypertension. This study aims to elucidate the specific mechanisms underlying the dysfunction of pulmonary artery vascular cells in broiler pulmonary hypertension, thereby enhancing our understanding of the pathogenesis of this syndrome.

THBS1 mediates hypoxia driven EndMT in pulmonary hypertension

Long-term hypoxia is one of the main causes of pulmonary vascular remodeling in pulmonary hypertension (PH) associated with congenital heart disease (CHD) children. Endothelial to mesenchymal transition (EndMT) is an important pathological basis of pulmonary vascular remodeling in PH. We observed that Fibronectin 1 (FN1) had strong protein-protein interactions with both Thrombospondin 1 (THBS1) and Transglutaminase 2 (TGM2) in PH with venous peripheral bloods samples from pediatric patients and healthy children. LungMAP CellCards and heatmaps of human PAEC in PH patients and lung tissues in hypoxia induced PH mice model were used to show that THBS1 and FN1 were significantly elevated. We studied the relationship between THBS1 and FN1 in vivo, by using SUHX-induced PH mice model, and in vitro, by using hypoxia-induced human PAEC. The results showed that hypoxia could result in EndMT and inhibiting THBS1 could reverse EndMT in vivo and in vitro, verifying our transcriptome results. Taken together, our research demonstrated that THBS1 could mediate hypoxia driven EndMT of PH, providing a new insight of research in the pathophysiology of PH.

Hypoxia as a potential inducer of immune tolerance, tumor plasticity and a driver of tumor mutational burden: Impact on cancer immunotherapy

In cancer patients, immune cells are often functionally compromised due to the immunosuppressive features of the tumor microenvironment (TME) which contribute to the failures in cancer therapies. Clinical and experimental evidence indicates that developing tumors adapt to the immunological environment and create a local microenvironment that impairs immune function by inducing immune tolerance and invasion. In this context, microenvironmental hypoxia, which is an established hallmark of solid tumors, significantly contributes to tumor aggressiveness and therapy resistance through the induction of tumor plasticity/heterogeneity and, more importantly, through the differentiation and expansion of immune-suppressive stromal cells. We and others have provided evidence indicating that hypoxia also drives genomic instability in cancer cells and interferes with DNA damage response and repair suggesting that hypoxia could be a potential driver of tumor mutational burden. Here, we reviewed the current knowledge on how hypoxic stress in the TME impacts tumor angiogenesis, heterogeneity, plasticity, and immune resistance, with a special interest in tumor immunogenicity and hypoxia targeting. An integrated understanding of the complexity of the effect of hypoxia on the immune and microenvironmental components could lead to the identification of better adapted and more effective combinational strategies in cancer immunotherapy. Clearly, the discovery and validation of therapeutic targets derived from the hypoxic tumor microenvironment is of major importance and the identification of critical hypoxia-associated pathways could generate targets that are undeniably attractive for combined cancer immunotherapy approaches.

Notch3/Hes5 Induces Vascular Dysfunction in Hypoxia-Induced Pulmonary Hypertension Through ER Stress and Redox-Sensitive Pathways

BACKGROUND

Notch3 (neurogenic locus notch homolog protein 3) is implicated in vascular diseases, including pulmonary hypertension (PH)/pulmonary arterial hypertension. However, molecular mechanisms remain elusive. We hypothesized increased Notch3 activation induces oxidative and endoplasmic reticulum (ER) stress and downstream redox signaling, associated with procontractile pulmonary artery state, pulmonary vascular dysfunction, and PH development.

METHODS

Studies were performed in TgNotch3R169C mice (harboring gain-of-function [GOF] Notch3 mutation) exposed to chronic hypoxia to induce PH, and examined by hemodynamics. Molecular and cellular studies were performed in pulmonary artery smooth muscle cells from pulmonary arterial hypertension patients and in mouse lung. Notch3-regulated genes/proteins, ER stress, ROCK (Rho-associated kinase) expression/activity, Ca2+ transients and generation of reactive oxygen species, and nitric oxide were measured. Pulmonary vascular reactivity was assessed in the presence of fasudil (ROCK inhibitor) and 4-phenylbutyric acid (ER stress inhibitor).

RESULTS

Hypoxia induced a more severe PH phenotype in TgNotch3R169C mice versus controls. TgNotch3R169C mice exhibited enhanced Notch3 activation and expression of Notch3 targets Hes Family BHLH Transcription Factor 5 (Hes5), with increased vascular contraction and impaired vasorelaxation that improved with fasudil/4-phenylbutyric acid. Notch3 mutation was associated with increased pulmonary vessel Ca2+ transients, ROCK activation, ER stress, and increased reactive oxygen species generation, with reduced NO generation and blunted sGC (soluble guanylyl cyclase)/cGMP signaling. These effects were ameliorated by N-acetylcysteine. pulmonary artery smooth muscle cells from patients with pulmonary arterial hypertension recapitulated Notch3/Hes5 signaling, ER stress and redox changes observed in PH mice.

CONCLUSIONS

Notch3 GOF amplifies vascular dysfunction in hypoxic PH. This involves oxidative and ER stress, and ROCK. We highlight a novel role for Notch3/Hes5-redox signaling and important interplay between ER and oxidative stress in PH.

Kidney Involvement in Systemic Sclerosis

Background: Systemic sclerosis is a chronic multisystem autoimmune disease, characterized by diffuse fibrosis and abnormalities of microcirculation and small arterioles in the skin, joints and visceral organs. Material and Methods: We searched for the relevant articles on systemic sclerosis and kidney involvement in systemic sclerosis in the NIH library of medicine, transplant, rheumatologic and nephrological journals. Results: Half of patients with systemic sclerosis have clinical evidence of kidney involvement. Scleroderma renal crisis represents the most specific and serious renal event associated with this condition. It is characterized by an abrupt onset of moderate to marked hypertension and kidney failure. Early and aggressive treatment is mandatory to prevent irreversible organ damage and death. The advent of ACE-inhibitors revolutionized the management of scleroderma renal crisis. However, the outcomes of this serious complication are still poor, and between 20 to 50% of patients progress to end stage renal disease. Conclusions: Scleroderma renal crisis still represents a serious and life-threatening event. Thus, further studies on its prevention and on new therapeutic strategies should be encouraged.