Polyethylene terephthalate microplastics (PET-MPs), a major microplastics component identified in human vasculature, pose emerging environmental health risks. This study systemically profiled MPs in human aortic tissues and investigated the mechanisms underlying PET-MPs-induced aortic injury in vivo and in vitro. Chronic oral exposure of Sprague-Dawley rats to PET-MPs (1.0-100 mg/L) resulted in endothelial glycocalyx loss and structural impairment of aortic elastic fibers, with MPs accumulating within aortic endothelial cells. Transcriptomic and biochemical analyses revealed that PET-MPs triggered endoplasmic reticulum stress (ERS) and reactive oxygen species (ROS) generation in human aortic endothelial cells (HAECs), driving glycocalyx degradation and NF-κB-mediated inflammation. Proteomic profiling identified endothelial-derived IL-1β as a key mediator, which subsequently induced phenotypic switching in human aortic smooth muscle cells (HASMCs) in vitro. Pharmacological inhibition of ERS (TUDCA), ROS (NAC), or IL-1β (Canakinumab) attenuated this pathogenic cascade. Crucially, restoration of the glycocalyx using Sulodexide mitigated endothelial dysfunction and downstream HASMC phenotypic switching. These findings establish endothelial glycocalyx degradation via ERS-ROS as a novel mechanism for PET-MPs-induced vascular injury and highlight glycocalyx protection as a potential strategy against environmental microplastic hazards.

Abstract Background Pulmonary hypertension (PH) involves progressive vascular remodeling and perivascular inflammation. Despite modest clinical improvements with current therapies, their limited ability to reverse remodeling or restore immune homeostasis highlights the need for novel agents. Liriodendrin (Lidd), derived from Sargentodoxae caulis , exhibits anti-inflammatory and antiproliferative activities, but its efficacy and molecular targets in PH are unknown. Methods Two well-established PH animal models - the SU5416/hypoxia (SuHx) mice model and monocrotaline (MCT)-induced rat model - were employed for in vivo assessment of Lidd conducted pharmacological effects. Primary human pulmonary artery smooth muscle cells (hPASMCs) were utilized for mechanistic investigations. RNA-sequencing (RNA-seq) analysis was conducted to identify potential signaling pathways modulated by Lidd treatment. The direct molecular target of Lidd was determined through integrated application of drug affinity responsive target stability (DARTS) assay coupled with western blot validation. To delineate histone lactylation-mediated transcriptional regulation, we combined Cleavage Under Targets and Tagmentation (CUT&Tag) sequencing data analysis followed by chromatin immunoprecipitation quantitative PCR (ChIP-qPCR) verification. Genetic validation was achieved using PFKFB3-deficient murine models to verify the specificity of Lidd-mediated pharmacological actions. Results Lidd administration attenuated pulmonary vascular remodeling, perivascular macrophage infiltration and PH progression in both SuHx and MCT models. Transcriptomic profiling of Lidd-treated hPASMCs revealed predominant enrichment of downregulated genes in inflammatory and cytokine-associated pathways. Mechanistically, Lidd directly bound PFKFB3 and enhanced its interaction with FZR1, promoting PFKFB3 ubiquitination and degradation, which reduced glycolysis-driven lactate and consequent histone lactylation. This, in turn, diminished transcriptional activation of proliferative and inflammatory mediators, including CCND1, TNC, and CCL2. Notably, exogenous lactate supplementation or endogenous lactate accumulation restored histone lactylation and paradoxically potentiated Lidd’s inhibitory effects on PASMC proliferation and migration, whereas p300 inhibition abrogated these lactate-mediated effects. Importantly, Lidd failed to confer additional protection in PFKFB3-deficient mice, confirming PFKFB3 as the primary target mediating its therapeutic action. Conclusion Our findings reveal that Lidd selectively targets the PFKFB3-mediated glycolytic-epigenetic axis to suppress PASMC phenotypic transformation and pulmonary vascular remodeling, positioning it as a promising therapeutic candidate for PH.

Background:Type 2 (T2)-high asthma with neutrophilic inflammation is characterized by airway eosinophilic and neutrophilic infiltration, hyperresponsiveness, remodeling, and insensitivity to steroid treatment. Sphingosine-1-phosphate (S1P), which has a crucial role in the development of asthma, promotes the proliferation and contraction of airway smooth muscle cells (ASMCs), contributing to the pathophysiological processes of asthma. However, the downstream mediator of S1P remains unclear, as does its role in T2-high asthma with neutrophilic inflammation. Methods:Ovalbumin- and ozone-induced murine models were used to replicate T2-high asthma with neutrophilic inflammation and primary ASMCs were applied to explore the underlying effects. Through transcriptomic analysis, PLK1 was identified as a potential key molecule associated with S1P-induced proliferation and contraction. Functional studies were performed both in vitro and in vivo by pharmacological inhibition to validate the role of PLK1 and to evaluate the therapeutic effects of PLK1 inhibition. Results:S1P level was elevated in the bronchoalveolar lavage fluid (BALF) of T2-high asthma with neutrophilic inflammation model, and promoted ASMCs proliferation and contraction. PLK1 expression increased in S1P-stimulated ASMCs and asthmatic lung tissues. Inhibition of PLK1 blocked S1P-induced ASMCs proliferation and contraction. In vivo, PLK1 inhibition reduced airway inflammation (particularly neutrophilic infiltration), airway remodeling (airway smooth muscle proliferation and collagen deposition), and airway hyperresponsiveness and resistance, improving lung function (of both large and small airways), with superior therapeutic effects to those of dexamethasone. In addition, PLK1 inhibition markedly reduced the BALF levels of IL-17A, IL-21 and IL-6, suggesting that PLK1 might exert its effects mainly through the regulation of Th17 pathway. Conclusion:PLK1 mediates S1P-induced ASMC proliferation and contraction, and plays an important part in T2-high asthma with neutrophilic inflammation model, making it a potential therapeutic target for treating T2-high asthma with neutrophilic inflammation.

Bacterial infection,excessive inflammatory response,and impaired angiogenesis caused by the hyperglycemic microenvironment of diabetic wounds are the primary factors of non-healing wounds.Most contemporary wound repair materials passively release loaded drugs,resulting in poor therapeutic outcomes.In this study,we designed sequentially triggered triple-responsive hydrogels containing alginate(ALG)-phenylboronic acid(PBA),copper polydopamine(Cu-PDA),metformin(MET),and deferoxamine mesylate(DFO)to cover the continuous process of diabetic-infected wound healing and improve the wound microenvironment through warming in the infectious phase and on-demand drug release in the inflammatory and proliferative phase.The hydrogels exhibited good adhesivity,injectability,self-healing ability,and biocompatibility.The hydrogels show remarkable photothermal responsiveness due to the presence of PDA.Studies showed that appropriate high temperatures and the release of Cu2+resulted in the hydrogels displaying excellent bactericidal properties in the infectious phase.Furthermore,the instability of the phenyl borate bond in a hyperglycemic and acidic microenvironment enables the glucose/pH responsiveness of the release of MET and DFO from the hydrogels.Mechanistic studies have shown that the hydrogels could suppress the activity of the NOD-,LRR-,and pyrin structural domain-containing protein 3(NLRP3)/caspase-1/GasderminD(GSDMD)/IL-1β pathway and activate the hypoxia-inducible factor 1 alpha(HIF-1α)/vascular endothelial growth factor(VEGF)pathway.These effects enabled the hydrogels to promote the healing of diabetic-infected wounds.

BACKGROUND:Pulmonary hypertension (PH) is a progressive and life-threatening disease characterized by pulmonary vascular remodeling, which involves aberrant proliferation and apoptosis resistance of the pulmonary arterial smooth muscle cells (PASMCs), resembling the hallmark characteristics of cancer. In cancer, the HMGB2 (high-mobility group box 2) protein promotes the pro-proliferative/antiapoptotic phenotype. However, the function of HMGB2 in PH remains uninvestigated. METHODS:Smooth muscle cell (SMC)-specific HMGB2 knockout or HMGB2-OE (HMGB2 overexpression) mice and HMGB2 silenced rats were used to establish hypoxia+Su5416 (HySu)-induced PH mouse and monocrotaline-induced PH rat models, respectively. The effects of HMGB2 and its underlying mechanisms were subsequently elucidated using RNA-sequencing and cellular and molecular biology analyses. Serum HMGB2 levels were measured in the controls and patients with pulmonary arterial (PA) hypertension. RESULTS:HMGB2 expression was markedly increased in the PAs of patients with PA hypertension and PH rodent models and was predominantly localized in PASMCs. SMC-specific HMGB2 deficiency or silencing attenuated PH development and pulmonary vascular remodeling in hypoxia+Su5416-induced mice and monocrotaline-treated rats. SMC-specific HMGB2 overexpression aggravated hypoxia+Su5416-induced PH. HMGB2 knockdown inhibited PASMC proliferation in vitro in response to PDGF-BB (platelet-derived growth factor-BB). In contrast, HMGB2 protein stimulation caused the hyperproliferation of PASMCs. In addition, HMGB2 promoted PASMC proliferation and the development of PH by RAGE (receptor for advanced glycation end products)/FAK (focal adhesion kinase)-mediated Hippo/YAP (yes-associated protein) signaling suppression. Serum HMGB2 levels were significantly increased in patients with PA hypertension, and they correlated with disease severity, predicting worse survival. CONCLUSIONS:Our findings indicate that targeting HMGB2 might be a novel therapeutic strategy for treating PH. Serum HMGB2 levels could serve as a novel biomarker for diagnosing PA hypertension and determining its prognosis.

Background and aims:The liver possesses a remarkable regenerative capacity in response to injuries or viral infections. Various growth factors and cytokines are involved in regulating liver regeneration. Prostaglandin (PG) D2, a pro-resolution lipid mediator, is the most abundant hepatic prostanoid. However, the role of PGD2 in the injury-induced liver regeneration remains unclear. Approach and results:Two-thirds partial hepatectomy (70% PH), massive hepatectomy (85% resection), and carbon tetrachloride-induced chronic injury were performed in mice to study the mechanisms of live regeneration. Hepatic PGD2 production was elevated in mice after PH. Global deletion of D prostanoid receptor (DP) 1, but not DP2, slowed PH-induced liver regeneration in mice, as evidenced by lower liver weight to body weight ratio, less Ki67+ hepatocyte proliferation, and G2/M phase hepatocytes. Additionally, DP1 deficiency specifically in resident Kupffer cells (KCs), and not in endothelial cells or hepatic stellate cells, retarded liver regeneration in mice post-PH. Conversely, the overexpression of exogenous DP1 in KCs accelerated liver regeneration in mice. Mechanistically, DP1 activation promoted Wnt2 transcription in a PKA/CREB-dependent manner in resident KCs and mediated hepatocyte proliferation through Frizzled8/beta-catenin signaling. Adeno-associated virus vector serotype 8 (AAV8)-mediated Frizzled8 knockdown in hepatocytes attenuated accelerated liver regeneration in KC-DP1 transgenic mice post-PH. Treatment with the DP1 receptor agonist BW245C promotes PH-induced liver regeneration in mice. Conclusions:DP1 activation mediates crosstalk between KCs and hepatocytes through Wnt2, and facilitates liver regeneration. Hence, DP1 may serve as a novel therapeutic target in acute and chronic liver diseases.

Vascular smooth muscle cells (VSMCs) are the major contributor to vascular repair and remodeling, which showed high level of phenotypic plasticity. Abnormalities in VSMC plasticity can lead to multiple cardiovascular diseases, wherein alternative splicing plays important roles. However, alternative splicing variants in VSMC plasticity are not fully understood. Here we systematically characterized the long-read transcriptome and their dysregulation in human aortic smooth muscle cells (HASMCs) by employing the Oxford Nanopore Technologies long-read RNA sequencing in HASMCs that are separately treated with platelet-derived growth factor, transforming growth factor, and hsa-miR-221-3P transfection. Our analysis reveals frequent alternative splicing events and thousands of unannotated transcripts generated from alternative splicing. HASMCs treated with different factors exhibit distinct transcriptional reprogramming modulated by alternative splicing. We also found that unannotated transcripts produce different open reading frames compared to the annotated transcripts. Finally, we experimentally validated the unannotated transcript derived from gene CISD1 , namely CISD1-u , which plays a role in the phenotypic switch of HASMCs. Our study characterizes the phenotypic modulation of HASMCs from an insight of long-read transcriptome, which would promote the understanding and the manipulation of HASMC plasticity in cardiovascular diseases.

Cancer nanomedicine combined with immunotherapy has emerged as a promising strategy for the treatment of cancer. However, precise regulation of the activation of antitumor immunity in targeting tissues for safe and effective cancer immunotherapy remains challenging. Herein, we report a tumor acidic microenvironment-responsive promodulator iron oxide nanoparticle (termed as FGR) with pH-activated action for photothermal-enhanced chemodynamic immunotherapy of cancer. FGR is formed via surface-modifying iron oxide nanoparticles with a dextran-conjugated Toll-like receptor agonist (R848) containing an acid-labile bond. In an acidic tumor microenvironment, the acid-responsive bonds are hydrolyzed to trigger the specific release of R848 to promote the maturation of dendritic cells. In addition, iron oxide nanoparticles within FGR exert photothermal and chemodynamic effects under near-infrared laser irradiation to directly kill tumor cells and induce immunogenic cell death. The synergistic effect of the released immunogenic factors and the acid-activated TLR7/8 pathway stimulates the formation of strong antitumor immunity, resulting in increased infiltration of cytotoxic CD8+ T cells into tumor tissues. As a result, FGR achieves acid-responsive on-demand release and activation of modulators in tumor sites and mediates photothermal-enhanced chemodynamic immunotherapy to inhibit the growth and metastasis of melanoma. Therefore, this work proposes a general strategy for designing prodrug nanomedicines to accurately regulate cancer immunotherapy.

Cardiovascular diseases are the leading cause of death worldwide. A chronic inflammatory response is a common pathological alteration in diverse cardiovascular diseases. Prostaglandin (PG) D2, a key lipid mediator derived from arachidonic acid metabolism, promotes resolution of inflammation and regulated T cell function through its receptors. Accumulated evidence has shown that dysregulated PGD2 signaling is involved in the pathogenesis of cardiovascular diseases, including atherosclerosis, hypertension, pulmonary hypertension, abdominal aortic aneurysm, and myocardial ischemia. Here, we summarized the recent progresses on PGD2 in cardiovascular homeostasis and discussed potential therapeutic translation by targeting PGD2 signaling.

Transcribed RNAs undergo various regulation and modification to become functional transcripts. Notably, cancer transcriptome has not been fully characterized at transcript resolution. Herein, we carry out a reference-based transcript assembly across >1000 cancer cell lines. We identify 498,255 transcripts, approximately half of which are unannotated. Unannotated transcripts are closely associated with cancer-related hallmarks and show clinical significance. We build a high-confidence RNA binding protein (RBP)-transcript regulatory network, wherein most RBPs tend to regulate transcripts involved in cell proliferation. We identify numerous transcripts that are highly associated with anti-cancer drug sensitivity. Furthermore, we establish RBP-transcript-drug axes, wherein PTBP1 is experimentally validated to affect the sensitivity to decitabine by regulating KIAA1522-a6 transcript. Finally, we establish a user-friendly data portal to serve as a valuable resource for understanding cancer transcriptome diversity and its potential clinical utility at transcript level. Our study substantially extends cancer RNA repository and will facilitate anti-cancer drug discovery.

Immunotherapy has been used for cancer treatment, while it faces the common dilemmas of low ther-apeutic efficacy and serious immunotoxicity. In this study, we report the construction of a tumor mi-croenvironment and near-infrared (NIR) light dual-responsive prodrug hydrogel for cancer synergistic immunotherapy in a more effective and safe manner. Such prodrug hydrogels were in-situ formed via calcium-induced gelation of alginate solution containing protoporphyrin IX (PpIX)-modified iron ox-ide (Fe3O4) nanoparticles and programmed death ligand 1 antibody (aPD-L1) prodrug nanoparticles crosslinked by reactive oxygen species (ROS)-responsive linkers. PpIX served as a photosensitizer to produce singlet oxygen ( 1 O 2 ) under NIR laser irradiation for photodynamic therapy (PDT), and Fe3O4 nanoparticles mediated chemodynamic therapy (CDT) to generate hydroxyl radical ( middotOH) via Fenton reac-tion in the tumor microenvironment. In view of the cumulative actions of PDT and CDT, amplified ROS was generated to not only induce immunogenic cell death (ICD), but also destroy ROS-responsive linkers to achieve on-demand release of aPD-L1 from prodrug nanoparticles. Boosted antitumor immunity was elicited in tumor-bearing mice due to the aPD-L1-mediated immune checkpoint blocking. As a result, the prodrug hydrogel-based synergistic immunotherapy could almost treat bilateral tumors and prevent lung and liver metastasis using 4T1 tumor mouse models. This study thus offers a dual-responsive prodrug hydrogel platform for precision cancer immunotherapy. Statement of significance Via calcium-induced gelation of alginate, we constructed a prodrug hydrogel with tumor microenviron-ment and near-infrared light dual-responsive action for synergistic cancer immunotherapy. Such hydro-gels can achieve on-demand release of aPD-L1 upon photoactivation in the tumor microenvironment. Through mediating photodynamic and chemodynamic therapy, the prodrug hydrogels can induce en-hanced immunogenic cell death and synergistically improve the efficacy of aPD-L1-mediated immune checkpoint blocking. The prodrug hydrogel-based synergistic therapy almost deracinates the primary and distant tumors, and prevents lung and liver metastasis in tumor mouse models.(c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Immunotherapy has recently been seen as a hopeful therapeutic device to inhibit tumor growth and metastasis, while the curative efficacy is limited by intrinsic immunosuppressive tumor microenvironment. Herein, we reported a tumor immunosuppressive microenvironment modulating hydrogel (TIMmH) platform to achieve second near-infrared (NIR-II) photothermal therapy (PTT) combined immunotherapy for durable inhibition of breast cancer. This TIMmH platform was synthesized through co-loading of NIR-II photothermal nanoagent and an immunoadjuvant cytosine-phosphateguanosine oligodeoxynucleotides (CpG ODNs) into the alginate hydrogel (ALG). Upon the administration of ALG into the tumor, the TIMmH was in situ formed via the coordination effect with Ca2+, locally encapsulating the semiconducting polymer nanoparticles (SPIIN) and CpG in the colloid, achieving to prolong the accumulation time and prevent the premature damage and release of immunotherapeutic agents. Upon 1064-nm photoirradiation, the TIMmHSD was able to elevate the intratumoral temperature for the ablation of tumors, which could induce the apoptosis of tumor cells and achieve thermal immune activation by regulating of an immunosuppressive microenvironment. The TIMmH-mediated combined treatment effectively suppressed the growths of breast cancers, and even acquired a sustained inhibition of the lung metastasis. This study provides a novel tumor immunosuppressive microenvironment modulating hydrogel platform with NIR-II photoexcited capacity for the safe, effective and durable lung metastasis-inhibiting breast cancer treatment.

Protein kinase A (PKA) plays an important role in regulating inflammation via its catalytic subunits. Recently, PKA regulatory subunits have been reported to directly modulate some signaling pathways and alleviate inflammation. However, the role of PKA regulatory subunits in colonic inflammation remains unclear. Therefore, we conducted this study to investigate the role of the PKA regulatory subunit PRKAR2A in colitis. We observed that PRKAR2A deficiency protected mice from dextran sulfate sodium (DSS)-induced experimental colitis. Our experiments revealed that the intestinal epithelial cell-specific deletion of Prkar2a contributed to this protection. Mechanistically, the loss of PRKAR2A in Prkar2a−/− mice resulted in an increased IFN-stimulated gene (ISG) expression and altered gut microbiota. Inhibition of ISGs partially reversed the protective effects against DSS-induced colitis in Prkar2a−/− mice. Antibiotic treatment and cross-fostering experiments demonstrated that the protection against DSS-induced colitis in Prkar2a−/− mice was largely dependent on the gut microflora. Altogether, our work demonstrates a previously unidentified function of PRKAR2A in promoting DSS-induced colitis.

Natural killer (NK) cell-mediated immunotherapy has shown a great promise for treatments of tumors, while some strategies that can improve its therapeutic efficacy and reduce potential adverse events are highly desired. We herein report a pH-sensitive second near-infrared (NIR-II) photothermal liposomal nanocomplex for enhanced NK cell-based immunotherapy of breast cancer. Such nanocomplex (LNCDS) consists of charge-transfer nanoparticles (CTN) with pH-sensitive NIR-II photothermal effect, deoxyribonuclease I (DNase I), NK cell stimulant (SIS3) and a surface coated thermal-responsive liposome shell. Upon 1064 nm laser irradiation, LNCDs generates mild heat in a controlled manner, which results in destruction of thermal-responsive liposome shell to allow on-demand release of stimulants and DNase I in tumor sites. The released DNase I not only kills cancer cells, but also induces immunogenic cell death (ICD), which synergizes with the action of the released SIS3 to promote activation of NK cells and cytotoxic T lymphocytes, contributing to enhanced therapeutic efficacy of immunotherapy. As a result, a single treatment of LNCDS upon NIR-II photoactivation greatly inhibits the growths of subcutaneously implanted primary and distant tumors in a breast cancer murine model, and even completely prevents lung metastasis. This study thus offers a photo-controlled drug delivery nanosystem for efficacy and precise NK cell-mediated immunotherapy of cancer. (C) 2021 Elsevier Ltd. All rights reserved.

Excessive deposition of extracellular matrix, mainly collagen protein, is the hallmark of organ fibrosis. The molecular mechanisms regulating fibrotic protein biosynthesis are unclear. Here, we find that chemoattractant receptor homologous molecule expressed on TH2 cells (CRTH2), a plasma membrane receptor for prostaglandin D2, is trafficked to the endoplasmic reticulum (ER) membrane in fibroblasts in a caveolin‐1‐dependent manner. ER‐anchored CRTH2 binds the collagen mRNA recognition motif of La ribonucleoprotein domain family member 6 (LARP6) and promotes the degradation of collagen mRNA in these cells. In line, CRTH2 deficiency increases collagen biosynthesis in fibroblasts and exacerbates injury‐induced organ fibrosis in mice, which can be rescued by LARP6 depletion. Administration of CRTH2 N‐terminal peptide reduces collagen production by binding to LARP6. Similar to CRTH2, bumetanide binds the LARP6 mRNA recognition motif, suppresses collagen biosynthesis, and alleviates bleomycin‐triggered pulmonary fibrosis in vivo. These findings reveal a novel anti‐fibrotic function of CRTH2 in the ER membrane via the interaction with LARP6, which may represent a therapeutic target for fibrotic diseases.

Background: Blood pressure often rises with aging, but exact mechanisms are still not completely understood. With aging, the level of proinflammatory cytokines increases in T lymphocytes. Prostaglandin D 2 , a proresolution mediator, suppresses Type 1 T helper (Th1) cytokines through D-prostanoid receptor 1 (DP1). In this study, we aimed to investigate the role of the prostaglandin D 2 /DP1 axis in T cells on age-related hypertension. Methods: To clarify the physiological and pathophysiological roles of DP1 in T cells with aging, peripheral blood samples were collected from young and older male participants, and CD4 + T cells were sorted for gene expression, prostaglandin production, and Western blot assays. Mice blood pressure was quantified by invasive telemetric monitor. Results: The prostaglandin D 2 /DP1 axis was downregulated in CD4 + T cells from older humans and aged mice. DP1 deletion in CD4 + T cells augmented age-related hypertension in aged male mice by enhancing Th1 cytokine secretion, vascular remodeling, CD4 + T cells infiltration, and superoxide production in vasculature and kidneys. Conversely, forced expression of exogenous DP1 in T cells retarded age-associated hypertension in mice by reducing Th1 cytokine secretion. Tumor necrosis factor α neutralization or interferon γ deletion ameliorated the age-related hypertension in DP1 deletion in CD4 + T cells mice. Mechanistically, DP1 inhibited Th1 activity via the PKA (protein kinase A)/p-Sp1 (phosphorylated specificity protein 1)/neural precursor cell expressed developmentally downregulated 4-like (NEDD4L) pathway–mediated T-box-expressed-in-T-cells (T-bet) ubiquitination. T-bet deletion or forced NEDD4L expression in CD4 + T cells attenuated age-related hypertension in CD4 + T cell–specific DP1-deficient mice. DP1 receptor activation by BW245C prevented age-associated blood pressure elevation and reduced vascular/renal superoxide production in male mice. Conclusions: The prostaglandin D 2 /DP1 axis suppresses age-related Th1 activation and subsequent hypertensive response in male mice through increase of NEDD4L–mediated T-bet degradation by ubiquitination. Therefore, the T cell DP1 receptor may be an attractive therapeutic target for age-related hypertension.

Rationale: Vascular remodeling, including smooth muscle cell hypertrophy and proliferation, is the key pathological feature of pulmonary arterial hypertension (PAH). Prostaglandin I2 analogs (beraprost, iloprost, and treprostinil) are effective in the treatment of PAH. Of note, the clinically favorable effects of treprostinil in severe PAH may be attributable to concomitant activation of DP1 (D prostanoid receptor subtype 1).Objectives: To study the role of DP1 in the progression of PAH and its underlying mechanism.Methods: DP1 levels were examined in pulmonary arteries of patients and animals with PAH. Multiple genetic and pharmacologic approaches were used to investigate DP1-mediated signaling in PAH.Measurements and Main Results: DP1 expression was downregulated in hypoxia-treated pulmonary artery smooth muscle cells and in pulmonary arteries from rodent PAH models and patients with idiopathic PAH. DP1 deletion exacerbated pulmonary artery remodeling in hypoxia-induced PAH, whereas pharmacological activation or forced expression of the DP1 receptor had the opposite effect in different rodent models. DP1 deficiency promoted pulmonary artery smooth muscle cell hypertrophy and proliferation in response to hypoxia via induction of mTORC1 (mammalian target of rapamycin complex 1) activity. Rapamycin, an inhibitor of mTORC1, alleviated the hypoxia-induced exacerbation of PAH in DP1-knockout mice. DP1 activation facilitated raptor dissociation from mTORC1 and suppressed mTORC1 activity through PKA (protein kinase A)-dependent phosphorylation of raptor at Ser791. Moreover, treprostinil treatment blocked the progression of hypoxia-induced PAH in mice in part by targeting the DP1 receptor.Conclusions: DP1 activation attenuates hypoxia-induced pulmonary artery remodeling and PAH through PKA-mediated dissociation of raptor from mTORC1. These results suggest that the DP1 receptor may serve as a therapeutic target for the management of PAH.

Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit prostaglandin (PG) formation by targeting cyclooxygenase (COX) 1 and 2. Long-term use of NSAIDs that selectively inhibit COX2 increases the risk for thrombotic events, cardiac failure, and hypertension. However, the underlying mechanisms remain unclear. In this study, COX1- and COX2-deficient rats were created via Cas9/RNA-mediated gene targeting. DNA genotyping and Western blot analysis confirmed successful generation of COX1(-/-)and COX2(-/-)rats. Adult COX1(-/-)rats grew normally, while more than 70% of COX2(-/-)rats after wean died within 2 months. Echocardiography showed markedly reduced left ventricular ejection fraction and fractional shortening in adult COX2(-/-)rats compared to those in wildtype (WT) controls. Histological analysis revealed accumulation of inflammatory cells and severe interstitial and perivascular fibrosis in COX2(-/-)cardiac tissues. Moreover, cardiac ATP and acetyl-CoA production was dramatically decreased in COX2(-/-)rats. Consistently, the expression of genes related to mitochondrial oxidation, such as those that encode for subunits of pyruvate dehydrogenase complex and acyl CoA dehydrogenases, were downregulated, while glycolytic hexokinase 1 (HK1) was upregulated in COX2(-/-)heart tissues. These observations indicate that COX2-deficient rats developed spontaneously heart failure, likely as a result of dysregulated cardiac energy metabolism.

The authors informed the journal that images shown in Figs 2E and 4B were incorrect. The HE staining of distal colon for WT and DP2 / mouse in Fig 2E, and the PK and DP1 immunofluorescence stainings in WT and DP1 / mouse colitis in Fig 4B are herewith corrected. The authors state that the results and conclusions of the article remain unchanged. The authors apologize for the oversight and any inconvenience it may have caused.