scholarly journals Defects in caveolin-1 cause dilated cardiomyopathy and pulmonary hypertension in knockout mice

2002 ◽  
Vol 99 (17) ◽  
pp. 11375-11380 ◽  
Author(s):  
Y.-Y. Zhao ◽  
Y. Liu ◽  
R.-V. Stan ◽  
L. Fan ◽  
Y. Gu ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Dilated Cardiomyopathy ◽  
Knockout Mice ◽  
Caveolin 1

PRMT5 Prevents Dilated Cardiomyopathy via Suppression of Protein O-GlcNAcylation

2021 ◽  
Author(s):  
Zhenhua Li ◽  
Jingping Xu ◽  
Yao Song ◽  
Chong Xin ◽  
Lantao Liu ◽  
...  
Keyword(s):  
Dilated Cardiomyopathy ◽  
Knockout Mice ◽  
Rna Splicing ◽  
Gene Knockout ◽  
Major Type ◽  
Integrated Analysis ◽  
Arginine Methyltransferase ◽  
Potential Strategy ◽  
Glcnac Transferase

Rationale: Protein O-GlcNAcylation is dynamically regulated by two key enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Excessive protein O-GlcNAcylation contributes to dilated cardiomyopathy (DCM), but its regulatory mechanisms are not fully understood. The protein arginine methyltransferase 5 (PRMT5) is the major type II arginine methyltransferase, which plays critical physiological roles by symmetrically dimethylating various downstream targets including proteins involved in RNA splicing. However, its function in regulating protein O-GlcNAcylation and DCM is unexplored. Objective: To elucidate the physiological function of PRMT5 and the mechanism underlying its role in regulating cardiac O-GlcNAcylation and homeostasis. Methods and Results: Conditional gene knockout was used to study the in vivo function of Prmt5 in regulating cardiac homeostasis. An integrated analysis of transcriptomic and metabolomic profiles was performed to investigate the molecular mechanism. Adeno-associated virus 9 (AAV9)-mediated gene delivery in the mouse was used to study the protein O-GlcNAcylation in Prmt5 deficiency-induced DCM. PRMT5 mRNA was decreased in human DCM hearts, and cardiomyocyte-specific Prmt5 deletion in mice resulted in DCM and heart failure. Transcriptomic and metabolomic profiling identified increased O-GlcNAcylation in the hearts of Prmt5-knockout mice. Mechanistically, Prmt5 deletion suppressed O-GlcNAcase (OGA) expression by inhibiting the transcription of Oga and triggering its aberrant splicing. Consistently, a positive correlation of PRMT5 and OGA was identified in human DCM hearts. Notably, gene therapy with AAV9 encoding the correctly spliced Oga normalized the cardiac protein O-GlcNAcylation levels and partially rescued the dilation and dysfunction of the hearts in Prmt5-knockout mice. Conclusions: Our data demonstrate a novel function of PRMT5 in regulating protein O-GlcNAcylation to maintain cardiac homeostasis, suggesting that targeting the PRMT5-OGA axis could be a potential strategy for treating DCM.

scholarly journals Caveolar peroxynitrite formation impairs endothelial TRPV4 channels and elevates pulmonary arterial pressure in pulmonary hypertension

2021 ◽  
Vol 118 (17) ◽  
pp. e2023130118
Author(s):  
Zdravka Daneva ◽  
Corina Marziano ◽  
Matteo Ottolini ◽  
Yen-Lin Chen ◽  
Thomas M. Baker ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Endothelial Cell ◽  
Arterial Pressure ◽  
Pulmonary Arterial Pressure ◽  
Pulmonary Arteries ◽  
Lung Edema ◽  
Structural Protein ◽  
Caveolin 1 ◽  
Pulmonary Arterial ◽  
Trpv4 Channel

Recent studies have focused on the contribution of capillary endothelial TRPV4 channels to pulmonary pathologies, including lung edema and lung injury. However, in pulmonary hypertension (PH), small pulmonary arteries are the focus of the pathology, and endothelial TRPV4 channels in this crucial anatomy remain unexplored in PH. Here, we provide evidence that TRPV4 channels in endothelial cell caveolae maintain a low pulmonary arterial pressure under normal conditions. Moreover, the activity of caveolar TRPV4 channels is impaired in pulmonary arteries from mouse models of PH and PH patients. In PH, up-regulation of iNOS and NOX1 enzymes at endothelial cell caveolae results in the formation of the oxidant molecule peroxynitrite. Peroxynitrite, in turn, targets the structural protein caveolin-1 to reduce the activity of TRPV4 channels. These results suggest that endothelial caveolin-1–TRPV4 channel signaling lowers pulmonary arterial pressure, and impairment of endothelial caveolin-1–TRPV4 channel signaling contributes to elevated pulmonary arterial pressure in PH. Thus, inhibiting NOX1 or iNOS activity, or lowering endothelial peroxynitrite levels, may represent strategies for restoring vasodilation and pulmonary arterial pressure in PH.

scholarly journals Chronic Hypoxia Decreases Endothelial Connexin 40, Attenuates Endothelium‐Dependent Hyperpolarization–Mediated Relaxation in Small Distal Pulmonary Arteries, and Leads to Pulmonary Hypertension

2020 ◽  
Vol 9 (24) ◽  
Author(s):  
Rui Si ◽  
Qian Zhang ◽  
Jody Tori O. Cabrera ◽  
Qiuyu Zheng ◽  
Atsumi Tsuji‐Hosokawa ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Pulmonary Hypertension ◽  
Right Ventricular ◽  
Knockout Mice ◽  
Chronic Hypoxia ◽  
Systolic Pressure ◽  
Right Ventricular Systolic Pressure ◽  
Ventricular Systolic Pressure ◽  
Pulmonary Endothelial Cells ◽  
Endothelium Dependent Relaxation

Background Abnormal endothelial function in the lungs is implicated in the development of pulmonary hypertension; however, there is little information about the difference of endothelial function between small distal pulmonary artery (PA) and large proximal PA and their contribution to the development of pulmonary hypertension. Herein, we investigate endothelium‐dependent relaxation in different orders of PAs and examine the molecular mechanisms by which chronic hypoxia attenuates endothelium‐dependent pulmonary vasodilation, leading to pulmonary hypertension. Methods and Results Endothelium‐dependent relaxation in large proximal PAs (second order) was primarily caused by releasing NO from the endothelium, whereas endothelium‐dependent hyperpolarization (EDH)–mediated vasodilation was prominent in small distal PAs (fourth–fifth order). Chronic hypoxia abolished EDH‐mediated relaxation in small distal PAs without affecting smooth muscle–dependent relaxation. RNA‐sequencing data revealed that, among genes related to EDH, the levels of Cx37 , Cx40 , Cx43 , and IK were altered in mouse pulmonary endothelial cells isolated from chronically hypoxic mice in comparison to mouse pulmonary endothelial cells from normoxic control mice. The protein levels were significantly lower for connexin 40 (Cx40) and higher for connexin 37 in mouse pulmonary endothelial cells from hypoxic mice than normoxic mice. Cx40 knockout mice exhibited significant attenuation of EDH‐mediated relaxation and marked increase in right ventricular systolic pressure. Interestingly, chronic hypoxia led to a further increase in right ventricular systolic pressure in Cx40 knockout mice without altering EDH‐mediated relaxation. Furthermore, overexpression of Cx40 significantly decreased right ventricular systolic pressure in chronically hypoxic mice. Conclusions These data suggest that chronic hypoxia‐induced downregulation of endothelial Cx40 results in impaired EDH‐mediated relaxation in small distal PAs and contributes to the development of pulmonary hypertension.

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