•A two sample Mendelian randomization approach was used to identify proteins, metabolites, or microbes that have a putative causal association with subcortical brain structure volumes.•Eleven ...proteins and six metabolites were found to have a significant association with subcortical structure volumes, with nine proteins and five metabolites being replicated using independent exposure data.•Heterogeneity and pleiotropy analysis showed low to no deviation from null thus validating our associations as truly significant.•The study highlighted the role of proteolytic and anti-oxidative components in the development and functioning of the brain.•The results provide novel insight for understanding subcortical brain structure changes and could help in uncovering potential diagnostic markers and drug targets for the many disorders that are associated with changes in brain structures.
Alterations in subcortical brain structure volumes have been found to be associated with several neurodegenerative and psychiatric disorders. At the same time, genome-wide association studies (GWAS) have identified numerous common variants associated with brain structure. In this study, we integrate these findings, aiming to identify proteins, metabolites, or microbes that have a putative causal association with subcortical brain structure volumes via a two-sample Mendelian randomization approach. This method uses genetic variants as instrument variables to identify potentially causal associations between an exposure and an outcome. The exposure data that we analyzed comprised genetic associations for 2994 plasma proteins, 237 metabolites, and 103 microbial genera. The outcome data included GWAS data for seven subcortical brain structure volumes including accumbens, amygdala, caudate, hippocampus, pallidum, putamen, and thalamus. Eleven proteins and six metabolites were found to have a significant association with subcortical structure volumes, with nine proteins and five metabolites replicated using independent exposure data. We found causal associations between accumbens volume and plasma protease c1 inhibitor as well as strong association between putamen volume and Agouti signaling protein. Among metabolites, urate had the strongest association with thalamic volume. No significant associations were detected between the microbial genera and subcortical brain structure volumes. We also observed significant enrichment for biological processes such as proteolysis, regulation of the endoplasmic reticulum apoptotic signaling pathway, and negative regulation of DNA binding. Our findings provide insights to the mechanisms through which brain volumes may be affected in the pathogenesis of neurodevelopmental and psychiatric disorders and point to potential treatment targets for disorders that are associated with subcortical brain structure volumes.
BACKGROUND:Angiotensin-converting enzyme 2 (ACE2) converts angiotensin II, a potent vasoconstrictor, to angiotensin-(1–7) and is also a membrane protein that enables coronavirus disease 2019 ...(COVID-19) infectivity. AMP-activated protein kinase (AMPK) phosphorylation of ACE2 enhances ACE2 stability. This mode of posttranslational modification of ACE2 in vascular endothelial cells is causative of a pulmonary hypertension (PH)–protective phenotype. The oncoprotein MDM2 (murine double minute 2) is an E3 ligase that ubiquitinates its substrates to cause their degradation. In this study, we investigated whether MDM2 is involved in the posttranslational modification of ACE2 through its ubiquitination of ACE2, and whether an AMPK and MDM2 crosstalk regulates the pathogenesis of PH.
METHODS:Bioinformatic analyses were used to explore E3 ligase that ubiquitinates ACE2. Cultured endothelial cells, mouse models, and specimens from patients with idiopathic pulmonary arterial hypertension were used to investigate the crosstalk between AMPK and MDM2 in regulating ACE2 phosphorylation and ubiquitination in the context of PH.
RESULTS:Levels of MDM2 were increased and those of ACE2 decreased in lung tissues or pulmonary arterial endothelial cells from patients with idiopathic pulmonary arterial hypertension and rodent models of experimental PH. MDM2 inhibition by JNJ-165 reversed the SU5416/hypoxia-induced PH in C57BL/6 mice. ACE2-S680L mice (dephosphorylation at S680) showed PH susceptibility, and ectopic expression of ACE2-S680L/K788R (deubiquitination at K788) reduced experimental PH. Moreover, ACE2-K788R overexpression in mice with endothelial cell–specific AMPKα2 knockout mitigated PH.
CONCLUSIONS:Maladapted posttranslational modification (phosphorylation and ubiquitination) of ACE2 at Ser-680 and Lys-788 is involved in the pathogenesis of pulmonary arterial hypertension and experimental PH. Thus, a combined intervention of AMPK and MDM2 in the pulmonary endothelium might be therapeutically effective in PH treatment.
Polycystic ovary syndrome (PCOS), a gynaecological endocrine disorder affects 9% of Indian women and is linked to type II diabetes. The association of INSR (INSulin Receptor gene) variants (rs2059807 ...and rs1799817) with PCOS was established through genome-wide association studies, yet requires validation for the Indian population. This case-control study included 253 PCOS women and 308 age-matched control. The minor allele frequency of rs2059807 had an odds ratio of 13.5 and that of rs1799817 was 11.8. The cohort with rs2059807 MAF presented elevated levels of luteinising hormone PCOS vs Control: 6.32 ± 2.26 mIU/mL vs 4.97 ± 3.27 mIU/mL, estradiol 116.01 ± 60.63 pg/mL vs 65.04 ± 44.98 pg/mL, and decreased HDL – C 50.4 ± 11.59 mg/dL vs 64 ± 15.49 mg/dL showing disturbances in the hormonal patterns. The rs1799817 polymorphism cohort had elevated levels of serum insulin 17.99 ± 11.6 mIU/mL vs 11.67 ± 6.63 mIU/mL, blood glucose 199.15 ± 63.72 mg/dL vs 96.6 ± 24.3 mg/dL, and testosterone 0.91 ± 0.2 nmol/L vs 0.53 ± 0.16 nmol/L thereby triggering metabolic dysfunction and predisposed to lifestyle disorder. Also, the SNPs were found to be in linkage equilibrium and contributed to the development of PCOS differentially.
Concentric pulmonary vascular wall thickening due partially to increased pulmonary artery (PA) smooth muscle cell (PASMC) proliferation contributes to elevating pulmonary vascular resistance (PVR) in ...patients with pulmonary hypertension (PH). Although pulmonary vasoconstriction may be an early contributor to increasing PVR, the transition of contractile PASMCs to proliferative PASMCs may play an important role in the development and progression of pulmonary vascular remodeling in PH. A rise in cytosolic Ca
concentration (Ca
) is a trigger for PASMC contraction and proliferation. Here, we report that upregulation of Piezo1, a mechanosensitive cation channel, is involved in the contractile-to-proliferative phenotypic transition of PASMCs and potential development of pulmonary vascular remodeling. By comparing freshly isolated PA (contractile PASMCs) and primary cultured PASMCs (from the same rat) in a growth medium (proliferative PASMCs), we found that Piezo1, Notch2/3, and CaSR protein levels were significantly higher in proliferative PASMCs than in contractile PASMCs. Upregulated Piezo1 was associated with an increase in expression of PCNA, a marker for cell proliferation, whereas downregulation (with siRNA) or inhibition (with GsMTx4) of Piezo1 attenuated PASMC proliferation. Furthermore, Piezo1 in the remodeled PA from rats with experimental PH was upregulated compared with PA from control rats. These data indicate that PASMC contractile-to-proliferative phenotypic transition is associated with the transition or adaptation of membrane channels and receptors. Upregulated Piezo1 may play a critical role in PASMC phenotypic transition and PASMC proliferation. Upregulation of Piezo1 in proliferative PASMCs may likely be required to provide sufficient Ca
to assure nuclear/cell division and PASMC proliferation, contributing to the development and progression of pulmonary vascular remodeling in PH.
Abstract
The molecular mechanisms leading to high-altitude pulmonary hypertension (HAPH) remains poorly understood. We previously analyzed the whole genome sequence of Kyrgyz highland population and ...identified eight genomic intervals having a potential role in HAPH. Tropomodulin 3 gene (TMOD3), which encodes a protein that binds and caps the pointed ends of actin filaments and inhibits cell migration, was one of the top candidates. Here we systematically sought additional evidence to validate the functional role of TMOD3. In-silico analysis reveals that some of the SNPs in HAPH associated genomic intervals were positioned in a regulatory region that could result in alternative splicing of TMOD3. In order to functionally validate the role of TMOD3 in HAPH, we exposed Tmod3−/+ mice to 4 weeks of constant hypoxia, i.e. 10% O2 and analyzed both functional (hemodynamic measurements) and structural (angiography) parameters related to HAPH. The hemodynamic measurements, such as right ventricular systolic pressure, a surrogate measure for pulmonary arterial systolic pressure, and right ventricular contractility (RV- ± dP/dt), increases with hypoxia did not separate between Tmod3−/+ and control mice. Remarkably, there was a significant increase in the number of lung vascular branches and total length of pulmonary vascular branches (P < 0.001) in Tmod3−/+ after 4 weeks of constant hypoxia as compared with controls. Notably, the Tmod3−/+ endothelial cells migration was also significantly higher than that from the wild-type littermates. Our results indicate that, under chronic hypoxia, lower levels of Tmod3 play an important role in the maintenance or neo-vascularization of pulmonary arteries.
Piezo is a mechanosensitive cation channel responsible for stretch-mediated Ca
and Na
influx in multiple types of cells. Little is known about the functional role of Piezo1 in the lung vasculature ...and its potential pathogenic role in pulmonary arterial hypertension (PAH). Pulmonary arterial endothelial cells (PAECs) are constantly under mechanic stretch and shear stress that are sufficient to activate Piezo channels. Here, we report that Piezo1 is significantly upregulated in PAECs from patients with idiopathic PAH and animals with experimental pulmonary hypertension (PH) compared with normal controls. Membrane stretch by decreasing extracellular osmotic pressure or by cyclic stretch (18% CS) increases Ca
-dependent phosphorylation (p) of AKT and ERK, and subsequently upregulates expression of Notch ligands, Jagged1/2 (Jag-1 and Jag-2), and Delta like-4 (DLL4) in PAECs. siRNA-mediated downregulation of Piezo1 significantly inhibited the stretch-mediated pAKT increase and Jag-1 upregulation, whereas downregulation of AKT by siRNA markedly attenuated the stretch-mediated Jag-1 upregulation in human PAECs. Furthermore, the mRNA and protein expression level of Piezo1 in the isolated pulmonary artery, which mainly contains pulmonary arterial smooth muscle cells (PASMCs), from animals with severe PH was also significantly higher than that from control animals. Intraperitoneal injection of a Piezo1 channel blocker, GsMTx4, ameliorated experimental PH in mice. Taken together, our study suggests that membrane stretch-mediated Ca
influx through Piezo1 is an important trigger for pAKT-mediated upregulation of Jag-1 in PAECs. Upregulation of the mechanosensitive channel Piezo1 and the resultant increase in the Notch ligands (Jag-1/2 and DLL4) in PAECs may play a critical pathogenic role in the development of pulmonary vascular remodeling in PAH and PH.
TRPC6, a therapeutic target for pulmonary hypertension Jain, Pritesh P; Lai, Ning; Xiong, Mingmei ...
American journal of physiology. Lung cellular and molecular physiology,
12/2021, Letnik:
321, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Idiopathic pulmonary arterial hypertension (PAH) is a fatal and progressive disease. Sustained vasoconstriction due to pulmonary arterial smooth muscle cell (PASMC) contraction and concentric ...arterial remodeling due partially to PASMC proliferation are the major causes for increased pulmonary vascular resistance and increased pulmonary arterial pressure in patients with precapillary pulmonary hypertension (PH) including PAH and PH due to respiratory diseases or hypoxemia. We and others observed upregulation of TRPC6 channels in PASMCs from patients with PAH. A rise in cytosolic Ca
concentration (Ca
) in PASMC triggers PASMC contraction and vasoconstriction, while Ca
-dependent activation of PI3K/AKT/mTOR pathway is a pivotal signaling cascade for cell proliferation and gene expression. Despite evidence supporting a pathological role of TRPC6, no selective and orally bioavailable TRPC6 antagonist has yet been developed and tested for treatment of PAH or PH. In this study, we sought to investigate whether block of receptor-operated Ca
channels using a nonselective blocker of cation channels, 2-aminoethyl diphenylborinate (2-APB, administered intraperitoneally) and a selective blocker of TRPC6, BI-749327 (administered orally) can reverse established PH in mice. The results from the study show that intrapulmonary application of 2-APB (40 µM) or BI-749327 (3-10 µM) significantly and reversibly inhibited acute alveolar hypoxia-induced pulmonary vasoconstriction. Intraperitoneal injection of 2-APB (1 mg/kg per day) significantly attenuated the development of PH and partially reversed established PH in mice. Oral gavage of BI-749327 (30 mg/kg, every day, for 2 wk) reversed established PH by ∼50% via regression of pulmonary vascular remodeling. Furthermore, 2-APB and BI-749327 both significantly inhibited PDGF- and serum-mediated phosphorylation of AKT and mTOR in PASMC. In summary, the receptor-operated and mechanosensitive TRPC6 channel is a good target for developing novel treatment for PAH/PH. BI-749327, a selective TRPC6 blocker, is potentially a novel and effective drug for treating PAH and PH due to respiratory diseases or hypoxemia.
Abstract
Pulmonary arterial hypertension (PAH) is a rare disease characterized by increased pulmonary pressure and vascular remodelling as a consequence of smooth muscle cell proliferation, ...endothelial cell dysfunction and inflammatory infiltrates. Meprin α is a metalloproteinase whose substrates include adhesion and cell–cell contact molecules involved in the process of immune cell extravasation. In this study, we aimed to unravel the role of meprin α in PAH-induced vascular remodelling. Our results showed that meprin α was present in the apical membrane of endothelial cells in the lungs and pulmonary arteries of donors and idiopathic PAH (IPAH) patients. Elevated circulating meprin α levels were detected in the plasma of IPAH patients. In vitro binding assays and electron microscopy confirmed binding of meprin α to the glycocalyx of human pulmonary artery endothelial cells (hPAECs). Enzymatic and genetic approaches identified heparan sulphate (HS) as an important determinant of the meprin α binding capacity to hPAEC. Meprin α treatment protected from excessive neutrophil infiltration and the protective effect observed in the presence of neutrophils was partially reversed by removal of HS from hPAEC. Importantly, HS levels in pulmonary arteries were decreased in IPAH patients and binding of meprin α to HS was impaired in IPAH hPAEC. In summary, our results suggest a role of HS in docking meprin α to the endothelium and thus in the modulation of inflammatory cell extravasation. In IPAH, the decreased endothelial HS results in the reduction of meprin α binding which might contribute to enhanced inflammatory cell extravasation and potentially to pathological vascular remodelling.
Cardioprotective benefits of ω-3 fatty acids such as docosahexaenoic acid (DHA) are well established, but the regulatory effect of DHA on vascular tone and pressure in pulmonary hypertension is ...largely unknown.As DHA is a potent regulator of K
channels, we hypothesised that DHA modulates the membrane potential of pulmonary artery smooth muscle cells (PASMCs) through K
channels and thus exerts its effects on pulmonary vascular tone and pressure.We show that DHA caused dose-dependent activation of the calcium-activated K
(KCa) current in primary human PASMCs and endothelium-dependent relaxation of pulmonary arteries. This vasodilation was significantly diminished in KCa
(Kcnma1
) mice. In vivo, acute DHA returned the right ventricular systolic pressure in the chronic hypoxia-induced pulmonary hypertension animal model to the level of normoxic animals. Interestingly, in idiopathic pulmonary arterial hypertension the KCa channels and their subunits were upregulated. DHA activated KCa channels in these human PASMCs and hyperpolarised the membrane potential of the idiopathic pulmonary arterial hypertension PASMCs to that of the PASMCs from healthy donors.Our findings indicate that DHA activates PASMC KCa channels leading to vasorelaxation in pulmonary hypertension. This effect might provide a molecular explanation for the previously undescribed role of DHA as an acute vasodilator in pulmonary hypertension.
An increase in pulmonary artery pressure is a common observation in adult mammals exposed to global alveolar hypoxia. It is considered a maladaptive response that places an increased workload on the ...right ventricle. The mechanisms initiating and maintaining the elevated pressure are of considerable interest in understanding pulmonary vascular homeostasis. There is an expectation that identifying the key molecules in the integrated vascular response to hypoxia will inform potential drug targets. One strategy is to take advantage of experiments of nature, specifically, to understand the genetic basis for the inter‐individual variation in the pulmonary vascular response to acute and chronic hypoxia. To date, detailed phenotyping of highlanders has focused on haematocrit and oxygen saturation rather than cardiovascular phenotypes. This review explores what we can learn from those studies with respect to the pulmonary circulation.
LINKED ARTICLES
This article is part of a themed issue on Risk factors, comorbidities, and comedications in cardioprotection. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.1/issuetoc
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