PPARγ

引言BRCC3 (BRCA1/BRCA2-containing complex亚基3)在特发性肺动脉高压患者和实验性肺动脉高压动物的肺组织中表达降低。激活素受体样激酶2 (ALK2)的BRCC3去泛素化激活了肺血管平滑肌细胞中TGF-β(转化生长因子-β)信号的BMP(骨形态发生蛋白)臂。BRCC3功能获得可能降低人类肺动脉高压易感性。2024年4月2日，扬州大学龚开政、加州大学圣地亚哥分校John Y.-J. Shyy及 Jason X.-J. Yuan共同通讯在Circulation（IF 38）在线发表题为“BRCC3 Regulation of ALK2 in Vascular Smooth Muscle Cells: Implication in Pulmonary Hypertension”的研究论文，该研究发现BRCC3通过维持BMP信号(即ALK2-Smad1/5-PPARγ轴)的完整性，同时抑制PASMCs中TGF-β信号，在维持肺血管稳态中起关键作用。在PAH患者和实验性肺动脉高压动物的pasmc中，BRCC3显著下调。BRCC3通过在Lys-472和Lys-475位点去泛素化ALK2，激活受体调控的Smad1/5/9 (Smad1/5/9)，从而导致BMP调控的PPARγ、p53和Id1的转录激活。BRCC3过表达也通过下调TGF-β表达和抑制Smad3磷酸化来减弱TGF-β信号传导。体外实验表明，BRCC3或去泛素样ALK2-K472/475R的过表达可减弱PASMC的增殖和迁移，增强PASMC的凋亡。在SM22α-BRCC3-Tg小鼠中，由于PASMCs中ALK2-Smad1/5-PPARγ轴的激活，肺动脉高压得到改善。相比之下，Brcc3-/-小鼠由于抑制ALK2-Smad1/5信号通路，对实验性肺动脉高压的易感性增加。总之，这些结果表明，BRCC3通过维持BMP信号(即ALK2-Smad1/5-PPARγ轴)的完整性，同时抑制PASMCs中TGF-β信号，在维持肺血管稳态中起关键作用。这种BMP/TGF-β通路的再平衡对于PAH的缓解具有重要的临床转化意义。BMPR2(骨形态发生蛋白2型受体)的突变和功能障碍与特发性和遗传性肺动脉高压(PAH)的发展有关。BMPR2在缺乏遗传原因的PAH患者中趋于下调，可能是由于炎症或环境影响。在BMP(骨形态发生蛋白)结合后，BMPR2结合并磷酸化其同源I型受体ALK2 (激活素受体样激酶-2；也被称为激活素A受体，I型)来激活BMP-BMPR2-Smad1/5/9信号级联。磷酸化的(p) Smad1/5/9易位进入细胞核，导致典型转录因子如Id1和非典型转录因子包括PPARγ和p53的激活，这些转录因子对肺动脉平滑肌细胞(PASMCs)发挥抗增殖和促凋亡作用。TGF-β(转化生长因子-β)或激活素-A结合后，TGF-β受体通过磷酸化Smad2/3发出信号，对肺血管细胞产生促增殖作用。然而，BMP和TGF-β臂对血管细胞的增殖、肥大、分化和存活有不同的影响，这取决于谱系和生物学背景。TGF-β家族受体(包括BMPR2/ALK2和TGF-β r2 /R1)和受体调节(R) Smads (Smad1/5/9或Smad2/3)的翻译后修饰(如磷酸化和泛素化)显著影响其活性，从而调节靶细胞命运。与K48相关的蛋白质泛素化通常与其蛋白酶体降解有关，而与K63相关的泛素化则参与多种细胞事件，包括DNA修复、细胞内蛋白质运输和激酶信号传导。SMURF1 (Smad泛素化调节因子1)作为HECT (E6AP C端同源)型E3泛素连接酶的成员，泛素化R-Smads (Smad1/5)进行蛋白酶体降解，从而阻断BMP信号传导。此外，SMURF1通过I-Smads对BMPRI和Smad1/5的降解，下调BMP信号。在实验性肺动脉高压(PH)啮齿动物中，SMURF1显著升高。然而，SMURF1是否介导多环芳烃肺血管中BMP成分蛋白的泛素化以及任何再平衡机制目前尚不清楚。BRCC3在PAH减轻中的保护作用示意图（Credit: Circulation）PASMCs向高增殖状态的表型变化与肺血管重构和小动脉肌肉化的发展有关。在PAH患者和实验性PH动物的PASMCs中，抗增殖BMP信号下调，而TGF-β、激活素和GDFs(生长分化因子)诱导的促增殖信号增强。事实上，ActRIIA(一种激活素受体IIA的融合蛋白配体陷阱)能够抑制促增殖TGF-β信号，降低肺血管阻力，提高PAH患者的生存率(PulSAR和STELLAR试验)。该研究表明，BRCC3水平在人类多环芳烃疾病和啮齿动物PH模型中较低。BRCC3通过在PASMCs中去泛素化ALK2激活ALK2-Smad1/5/9-PPAR γ轴。因此，BRCC3似乎在疾病发病机制中拮抗SMURF1，上调和激活BRCC3可能是PAH/PH的一种新的治疗策略。原文链接https://doi-org.libproxy1.nus.edu.sg/10.1161/CIRCULATIONAHA.123.066430责编|探索君排版|探索君文章来源|“iNature”End往期精选围观一文读透细胞死亡(Cell Death) | 24年Cell重磅综述（长文收藏版）热文Nature | 破除传统：为何我们需要重新思考肿瘤的命名方式热文Nature | 2024年值得关注的七项技术热文Nature | 自身免疫性疾病能被治愈吗？科学家们终于看到了希望热文CRISPR技术进化史 | 24年Cell综述

引言怀孕期间昼夜节律的破坏会对后代产生不利的健康后果；然而，母体昼夜节律在婴儿免疫系统中的作用及其对炎症的易感性仍然知之甚少。2024年4月1日，天津医科大学周洁、刘强及余鹰共同通讯在Nature Metabolism 在线发表题为“Maternal circadian rhythm disruption affects neonatal inflammation via metabolic reprograming of myeloid cells”的研究论文，该研究证明，怀孕小鼠昼夜节律的破坏大大加重了雄性和雌性后代的新生儿炎症性疾病的严重程度，如坏死性小肠结肠炎和败血症。母体产生二十二碳六烯酸(DHA)的减少和新生儿髓源性抑制细胞(MDSCs)的免疫抑制功能受损导致了这一现象。机制上，DHA通过PPARγ介导的线粒体氧化磷酸化增强MDSCs的免疫抑制功能。转移MDSCs或围产期补充DHA可减轻由母体节律紊乱引起的新生儿炎症。这些观察结果共同证明了母体昼夜节律在通过骨髓细胞代谢重编程控制新生儿炎症中的作用，这是以前未被认识到的。昼夜节律是一种自我延续的振荡和对24小时周期的适应，它与外部环境信号同时同步，影响几乎所有的生理活动。昼夜节律是由转录激活因子(CLOCK/BMAL1)及其抑制因子(PERs/CRYs/REV-ERBs)组成的调节反馈回路控制的。新出现的证据已经证明了昼夜节律在免疫系统中的重要性：不同免疫细胞的细胞结构、迁移和功能都受到昼夜节律的调节。昼夜节律的破坏会导致各种免疫相关疾病。流行病学研究和动物模型都表明，怀孕期间的次优刺激会使后代对多种疾病（包括免疫相关疾病）的易感性更高。母体昼夜节律的紊乱会导致不良的妊娠结局，如早产，甚至对成年后代的健康产生长期的恶化影响。然而，母体昼夜节律在后代免疫系统中的作用的详细机制仍然知之甚少。围产期补充DHA可减轻CRD模型新生儿炎症（Credit: Nature Metabolism）新生儿在出生后立即暴露于高水平的外来抗原，其中大多数是无害的，例如定植微生物群。为了避免对这些外来抗原的过度免疫激活和过度炎症，婴儿保持相对免疫耐受。婴儿期早期短暂出现的调节性免疫细胞，如MDSCs，有助于通过诱导免疫耐受来控制炎症。早产儿或低体重婴儿由于无法维持免疫耐受，患坏死性小肠结肠炎(NEC)等炎症性疾病的风险更高。母亲的昼夜节律是否会影响婴儿早期炎症性疾病的风险，这在很大程度上仍然未知。该研究通过动物模型探讨了母体昼夜节律对新生儿炎症的潜在影响。由昼夜节律紊乱的母鼠分娩的幼崽表现出更高的NEC和败血症死亡率。母体来源DHA的减少和新生儿骨髓细胞功能受损解释了这种疾病的表型。DHA通过PPARγ介导的脂肪酸摄取和线粒体ATP生成增强新生儿髓细胞的免疫抑制功能。MDSCs的被动转移或围产期DHA补充抵消了母亲昼夜节律中断对新生儿炎症的影响。这些观察结果揭示了母体昼夜节律在新生儿炎症限制中的重要性。原文链接https://www-nature-com.libproxy1.nus.edu.sg/articles/s42255-024-01021-y责编|探索君排版|探索君文章来源|“iNature”End往期精选围观一文读透细胞死亡(Cell Death) | 24年Cell重磅综述（长文收藏版）热文Nature | 破除传统：为何我们需要重新思考肿瘤的命名方式热文Nature | 2024年值得关注的七项技术热文Nature | 自身免疫性疾病能被治愈吗？科学家们终于看到了希望热文CRISPR技术进化史 | 24年Cell综述

Completed patient enrollment in the Phase II MAvERIC-Pilot study evaluating CardiolRx™ in patients with recurrent pericarditis, with topline results expected in Q2 2024 CardiolRx™ granted U.S. FDA Orphan Drug Designation for the treatment of pericarditis, which includes recurrent pericarditis Exceeded 50% enrollment in the Phase II ARCHER trial evaluating CardiolRx™ in patients with acute myocarditis; study expected to reach full enrollment during Q3 2024 Data presented at the HFSA Annual Scientific Sessions 2023 demonstrated that the API in Cardiol's novel CRD-38 formulation attenuates harmful fat distribution and key markers of cardiac inflammation and remodelling in a model of heart failure with preserved ejection fraction Cash and cash equivalents of $34.9 million as of December 31, 2023, which funds operations into 2026 Toronto, Ontario--(News - April 2, 2024) - Cardiol Therapeutics Inc. (NASDAQ: CRDL) (TSX: CRDL) ("Cardiol" or the "Company"), a clinical-stage life sciences company focused on the research and clinical development of anti-inflammatory and anti-fibrotic therapies for the treatment of heart disease, today announces its year-end 2023 update on operations following the filing of its audited Financial Statements and Management's Discussion and Analysis for the year ended December 31, 2023. Both are available under the Company's pro SEDAR+ at sedarplus.ca and on the Company's website at cardiolrx.com. "Cardiol Therapeutics made important progress in 2023 and early 2024 as we pursued our primary objective of providing new therapeutic options to patients with poorly served heart diseases," said David Elsley, President and Chief Executive Officer of Cardiol Therapeutics. "During 2023, we initiated patient recruitment in our MAvERIC-Pilot study in patients with recurrent pericarditis and are very pleased that this important study recently completed full target enrollment, positioning the Company to report topline results in the second quarter of 2024. Completion of patient enrollment in MAvERIC-Pilot was achieved shortly after receipt of U.S. FDA Orphan Drug Designation for CardiolRx™ for the treatment of pericarditis, a larger indication and potential market exclusivity than originally anticipated by the Company. Another noteworthy clinical milestone of 2023 culminated with reporting that our global ARCHER trial, which is evaluating CardiolRx™ in patients with acute myocarditis, exceeded 50% enrollment, and is now expected to complete full enrollment during the third quarter of 2024 which is ahead of the original timeline. Importantly, CardiolRx™ is also eligible for orphan drug designations for the treatment of acute myocarditis in both the United States and the European Union. In support of our ongoing clinical programs, we were pleased to have pre-clinical results presented by our collaborators at a number of cardiology-focused scientific meetings throughout 2023, providing additional insight into the molecular and cellular mechanisms of action and benefits of our drug candidates. Looking forward, with operations funded into 2026, Cardiol is well positioned to achieve significant milestones in the MAvERIC, ARCHER, and CRD-38 programs during 2024 that we believe will underpin business development initiatives aimed at accelerating our goal of delivering important new therapeutic options to people affected by underserved debilitating heart diseases." Key Highlights: Phase II MAvERIC-Pilot Study in Recurrent Pericarditis In January 2023, Cardiol announced the first patient had been enrolled in the Company's Phase II open-label pilot study ("MAvERIC-Pilot") investigating the tolerance, safety, and efficacy of CardiolRx™ in patients with recurrent pericarditis. In addition to standard safety assessments, the study is designed to evaluate improvement in objective measures of disease, and during an extension period, assess the feasibility of weaning concomitant background therapy including corticosteroids, while taking CardiolRx™. In November 2023, Cardiol announced that it had exceeded 50% of the patient enrollment target for the MAvERIC-Pilot study. Furthermore, in December, Cardiol announced that Massachusetts General Hospital had been initiated and was eligible to enroll patients; adding to a pre-eminent group of medical research centers participating in the study that includes the Cleveland Clinic and the Mayo Clinic. In February 2024, CardiolRx™ was granted Orphan Drug Designation ("ODD") by the United States Food and Drug Administration ("FDA") for the treatment of pericarditis, a rare inflammatory heart disease. The FDA grants ODD to a drug or biological product to prevent, diagnose, or treat a rare disease or condition that affects fewer than 200,000 people in the United States. ODD provides benefits to sponsors including potential seven-year marketing exclusivity, exemptions from certain FDA fees, and tax credits for qualified clinical trials. Products with ODD may also qualify for accelerated regulatory review via Fast Track, Breakthrough Therapy, or Priority Review designations. In February 2024, Cardiol announced the completion of patient enrollment in MAvERIC-Pilot. In addition, the Company announced that it expects to report topline results from MAvERIC-Pilot in Q2 2024. Phase II ARCHER Trial in Acute Myocarditis In September 2023, Cardiol announced that all collaborating research centers had been initiated and were eligible to enroll patients in ARCHER, the Company's Phase II, multi-center, international, double-blind, randomized, placebo-controlled trial designed to study the safety and tolerability of CardiolRx™, as well as its impact on myocardial recovery, in patients presenting with acute myocarditis. ARCHER is expected to enroll approximately 100 patients at major cardiac centers in North America, Europe, Latin America, and Israel. In January 2024, Cardiol announced that ARCHER had exceeded 50% patient enrollment and was progressing ahead of the original study timeline. The Company anticipates completing full enrollment in Q3 2024. Given there are no FDA-approved therapies for acute myocarditis, Cardiol believes there is a significant opportunity to develop an important new therapy for acute myocarditis that would also be eligible for orphan designation in the United States and the European Union. Pre-Clinical/Clinical Developments In March, Cardiol announced study results were presented at the American College of Cardiology's 72nd Annual Scientific Session together with World Congress of Cardiology demonstrating that the active pharmaceutical ingredient ("API") in CardiolRx™ and CRD-38 (a novel subcutaneously administered formulation), significantly prevents cardiac dysfunction and the development of fibrosis and cardiomyocyte hypertrophy in a pre-clinical model of heart failure and reduces expression of key inflammatory and fibrotic markers. This work builds upon existing knowledge by confirming the cardioprotective properties of Cardiol's lead small molecule drug candidate and, in this model, its ability to reduce inflammation and prevent hypertrophy and fibrosis in heart tissue. A second poster presented data related to the role of the API in mitochondrial calcium dynamics in hypertrophic cells. The API was shown to prevent hypertrophy-induced mitochondrial calcium overload and prevent hypertrophy-induced increase of several mitochondrial function markers such as reactive oxygen species and calcium uptake. In addition, this work suggests that the API effects may rely on PPAR-γ activation, which in turn can inhibit NF-κB, a transcription factor that regulates pro-inflammatory and pro-hypertrophic genes. Together, these findings further clarify the API's mode of action in combatting cardiac hypertrophy. In October, Cardiol announced study results presented at the Heart Failure Society of America ("HFSA") Annual Scientific Meeting 2023 demonstrating that the subcutaneously administered formulation of the API slowed increases in body weight and heart weight and prevented increases in key cardiac inflammatory and remodelling markers in a pre-clinical model of heart failure with preserved ejection fraction. These findings expand the understanding of the cardioprotective effects of CRD-38 and suggest new therapeutic potential in heart failure, which remains a leading cause of death and hospital admissions in the United States and throughout the developed world, with associated healthcare costs in the United States exceeding US$30 billion annually. In November, Cardiol announced results from experiments conducted by its research collaborators at the University of Virginia and Houston Methodist DeBakey Heart & Vascular Center, that in an experimental model of pericarditis, the API induces mesothelial to mesenchymal transition ("MMT") and that this process is inhibited by treatment. The results presented were a continuation of a research collaboration between Cardiol and the University of Virginia, which previously reported at the American Heart Association Scientific Sessions 2022 that the API reduces pericardial effusion and thickness in the same experimental model of pericarditis. MMT is a complex and stepwise biological process whereby a mesothelial cell, the main cell type lining internal organs and several of the body's internal cavities including the pericardium, undergoes molecular reprogramming. This alters its characteristics towards a mesenchymal cell, such as a myofibroblast, which are the primary cells during wound healing and fibrosis. Mounting evidence indicates the transition to mesenchymal cells is involved in adult cardiovascular diseases, such as heart failure. Pericarditis leads to pericardial effusion and thickening that may evolve to fibrosis, and by limiting MMT and the ensuing fibrosis, CardiolRx™ may also represent a novel strategy to prevent pericarditis complications. About Cardiol Therapeutics Cardiol Therapeutics Inc. (NASDAQ: CRDL) (TSX: CRDL) is a clinical-stage life sciences company focused on the research and clinical development of anti-inflammatory and anti-fibrotic therapies for the treatment of heart disease. The Company's lead small molecule drug candidate, CardiolRx™ (cannabidiol) oral solution, is pharmaceutically manufactured and in clinical development for use in the treatment of heart disease. It is recognized that cannabidiol inhibits activation of the inflammasome pathway, an intracellular process known to play an important role in the development and progression of inflammation and fibrosis associated with myocarditis, pericarditis, and heart failure. Cardiol has received Investigational New Drug Application authorization from the United States Food and Drug Administration ("US FDA") to conduct clinical studies to evaluate the efficacy and safety of CardiolRx™ in two diseases affecting the heart: (i) a Phase II multi-center open-label pilot study in recurrent pericarditis (the MAvERIC-Pilot study; NCT05494788), an inflammatory disease of the pericardium which is associated with symptoms including debilitating chest pain, shortness of breath, and fatigue, and results in physical limitations, reduced quality of life, emergency department visits, and hospitalizations; and (ii) a Phase II multi-national, randomized, double-blind, placebo-controlled trial (the ARCHER trial; NCT05180240) in acute myocarditis, an important cause of acute and fulminant heart failure in young adults and a leading cause of sudden cardiac death in people less than 35 years of age. The US FDA has granted Orphan Drug Designation to CardiolRx™ for the treatment of pericarditis, which includes recurrent pericarditis. Cardiol is also developing CRD-38, a novel subcutaneously administered drug formulation of cannabidiol intended for use in heart failure – a leading cause of death and hospitalization in the developed world, with associated healthcare costs in the United States exceeding $30 billion annually. For more information about Cardiol Therapeutics, please visit cardiolrx.com. Cautionary statement regarding forward-looking information: This news release contains "forward-looking information" within the meaning of applicable securities laws. All statements, other than statements of historical fact, that address activities, events, or developments that Cardiol believes, expects, or anticipates will, may, could, or might occur in the future are "forward-looking information". Forward-looking information contained herein may include, but is not limited to, statements relating to the Company's focus on developing anti-inflammatory and anti-fibrotic therapies for the treatment of heart disease, the molecular targets and mechanism of action of the Company's product candidates, the Company's intended clinical studies and trial activities and timelines associated with such activities, including for primary efficacy endpoint and secondary endpoints, the Company's plan to advance the development of a novel subcutaneous formulation of CardiolRx™ for use in heart failure, and the Company's expectation to report topline results from MAvERIC-Pilot in the second quarter of 2024 and that these results will inform the design of a pivotal Phase III clinical trial in recurrent pericarditis to underpin the potential regulatory approval of CardiolRx™, the Company's plan to complete full enrollment of approximately 100 patients at major cardiac centers in North America, Europe, Latin America, and Israel in the ARCHER trial during the third quarter of 2024, the Company's belief that its product candidates may be eligible for orphan drug designation in the United States and the European Union as a therapy for acute myocarditis, the Company's expectation that operations will be funded into 2026 and the Company's expectation that it will achieve significant corporate milestones during 2024. Forward-looking information contained herein reflects the current expectations or beliefs of Cardiol based on information currently available to it and is based on certain assumptions and is also subject to a variety of known and unknown risks and uncertainties and other factors that could cause the actual events or results to differ materially from any future results, performance or achievements expressed or implied by the forward-looking information, and are not (and should not be considered to be) guarantees of future performance. These risks and uncertainties and other factors include the risks and uncertainties referred to in the Company's Annual Report on Form 20-F dated April 1, 2024, as well as the risks and uncertainties associated with product commercialization and clinical studies. These assumptions, risks, uncertainties, and other factors should be considered carefully, and investors should not place undue reliance on the forward-looking information, and such information may not be appropriate for other purposes. Any forward-looking information speaks only as of the date of this press release and, except as may be required by applicable securities laws, Cardiol disclaims any intent or obligation to update or revise such forward-looking information, whether as a result of new information, future events, or results, or otherwise. For further information, please contact: Trevor Burns, Investor Relations +1-289-910-0855 trevor.burns@cardiolrx.com To view the source version of this press release, please visit