eNOS-Dependent Mechanoregulation of Intraocular Pressure

eNOS 依赖性眼压机械调节

• 批准号: 10701730
• 负责人: DARRYL R OVERBY
• 金额: $ 43.49万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10701730
• 关键词: Acute; Aqueous Humor; Blood-Aqueous Barrier; Cells; Chronic; Data; Development; Disease Progression; Drainage procedure; Endothelial Cells; Endothelium; Extracellular Matrix; Eye; Feedback; Flushing; Functional disorder; Funding; Generations; Glaucoma; Health; Homeostasis; Knowledge; Legal patent; Mediating; Medical; Molecular; NG-Nitroarginine Methyl Ester; Nitric Oxide; Obstruction; Ocular Hypertension; Open-Angle Glaucoma; Outcome Study; Particulate; Particulate Matter; Pathology; Pathway interactions; Patients; Permeability; Pharmaceutical Preparations; Physiologic Intraocular Pressure; Physiologic pulse; Pigments; Primary Open Angle Glaucoma; Process; Production; Progress Reports; Relaxation; Research; Resistance; Rho-associated kinase; Role; Signal Transduction; Signaling Molecule; Source; Stretching; Structure of sinus venosus of sclera; Study models; Testing; Therapeutic; Time; Tissues; Trabecular meshwork structure; Vascular Endothelium; desensitization; insight; kinase inhibitor; neuroprotection; novel; ocular surface; pressure; response; shear stress; success; targeted treatment

Ocular hypertension in glaucoma arises from increased drainage resistance for aqueous humor in the conventional outflow pathway, which includes the trabecular meshwork (TM) and Schlemm’s canal (SC). Unfortunately, the cellular mechanisms responsible for resistance generation are largely unknown. Our previous funding cycles have demonstrated that nitric oxide (NO) is a key regulator of outflow resistance and intraocular pressure (IOP). Moreover, we have shown that shear stress stimulates NO production by SC endothelial cells, like vascular endothelia. Further, the magnitude of shear stress acting on SC cells depends on IOP, due to pressure-induced narrowing of the SC lumen. As NO is known to decrease outflow resistance, shear-induced NO production may act as a “fast” homeostatic signal to oppose the source of IOP elevation and help to maintain IOP in a narrow range. This “fast” homeostasis is sensed by SC shear stress and operates over time scales of seconds to minutes, and contrasts with the “slow” IOP homeostasis that is sensed by TM stretch that stimulates extracellular matrix (ECM) remodeling over several days. These “fast” and “slow” mechanisms are complementary because they allow the outflow pathway to sense and respond to perturbations in outflow function over a range of temporal scales, from acute outflow obstruction to chronic remodeling of ECM. Our recent data provide further insight into the homeostatic role of NO and how NO maintains the health and function of the conventional outflow pathway. For example, our data show that NO production by SC cells is amplified by pulsatile shear stress, which arises due to the ocular pulse and results in an immediate pulsation-induced decrease in outflow resistance. We also show that NO contributes to the clearance of particulate matter, such as pigment and cell debris, that would naturally accumulate in the juxtacanalicular TM. Thirdly, our modelling studies suggest that elevated TM stiffness (as occurs in primary open angle glaucoma; POAG) eliminates the “fast” IOP homeostasis by suppressing pulsation-induced shear stress in SC. Consequently, this desensitization allows debris to accumulate unchecked in the TM, leading to eventual outflow dysfunction and IOP elevation. Taken together, our central hypothesis is that NO has two critical roles in maintaining IOP homeostasis over short time scales: (i) as a key signaling molecule in a mechanosensitive feedback loop potentiated by pulsatile shear stress in the SC lumen, and (ii) as a modulator of inner wall permeability and TM contractility to flush cell debris/pigment from the juxtacanalicular TM. We test our hypothesis with three Specific Aims (SAs). SA1: To determine how the ocular pulse modulates outflow facility through NO signaling. SA2: To determine how NO contributes to IOP homeostasis in response to particulate load in the TM. SA3: To determine how NO regulates inner wall permeability, enabling particulate clearance from the TM. Impact: Outcomes from this study will dissect the multifaceted role of NO signaling in IOP homeostasis, allowing us to exploit this knowledge for the development of targeted, SC-based therapeutics for patients with POAG.

青光眼高眼压是由于房水滤过阻力增加所致。 常规流出途径，包括小梁网(TM)和Schlemm管(SC)。 不幸的是，导致抗性产生的细胞机制在很大程度上是未知的。我们以前的 资金周期表明，一氧化氮(NO)是流出阻力和眼内的关键调节因子。 压力(眼压)。此外，我们还表明，剪切力刺激SC内皮细胞产生NO， 就像血管内皮细胞。此外，作用于SC细胞的剪应力的大小取决于眼压，这是由于 压力引起的SC管腔狭窄。众所周知，NO可降低剪切诱导的流出阻力 NO的产生可能起到“快速”动态平衡信号的作用，以对抗眼压升高的来源并帮助维持 眼压在狭窄范围内。这种“快速”的动态平衡是由SC剪应力感知的，并在时间尺度上运行 几秒到几分钟，与TM伸展所感觉到的刺激眼压的“缓慢”眼压稳态形成鲜明对比 细胞外基质(ECM)在几天内重塑。这些“快”和“慢”的机制是 互补性，因为它们允许流出路径感知并响应流出中的扰动 在一系列时间尺度上发挥作用，从急性流出道梗阻到慢性ECM重塑。我们的 最近的数据进一步揭示了NO在体内平衡中的作用，以及NO如何维持健康和功能 传统的流出路径。例如，我们的数据显示，干细胞产生的NO被放大 脉动切应力，由眼球脉搏产生，并导致立即脉动诱导 流出阻力减小。我们还表明，NO有助于颗粒物的清除，如 作为色素和细胞碎片，它们会自然积累在邻近的TM中。第三，我们的造型 研究表明，TM硬度增加(发生在原发性开角型青光眼；POAG)可以消除 通过抑制SC中脉动诱导的切应力实现眼压的“快速”动态平衡。因此，这种脱敏作用 允许碎片在TM内无节制地堆积，最终导致流出功能障碍和眼压升高。 综上所述，我们的中心假设是，一氧化氮在维持眼压动态平衡方面有两个关键作用。 短时间尺度：(I)作为机械敏感反馈环中的关键信号分子 SC管腔内的剪应力，以及(Ii)作为内壁通透性和TM收缩能力的调节器来冲洗细胞 来自邻近TM的碎屑/颜料。我们用三个特定的目标(SA)来检验我们的假设。 SA1：确定眼脉如何通过NO信号调节流出功能。 SA2：确定在TM的颗粒负荷反应中，NO如何促进眼压的稳态。 SA3：确定NO如何调节内壁渗透性，使颗粒能够从TM清除。 影响：这项研究的结果将剖析NO信号在眼压动态平衡中的多方面作用，允许 我们希望利用这一知识为POAG患者开发有针对性的、以SC为基础的疗法。

项目成果

Measurement of postmortem outflow facility using iPerfusion.

• DOI: 10.1016/j.exer.2022.109103
• 发表时间: 2022-07
• 期刊: EXPERIMENTAL EYE RESEARCH
• 影响因子: 3.4
• 作者: Madekurozwa, Michael;Reina-Torres, Ester;Overby, Darryl R.;van Batenburg-Sherwood, Joseph
• 通讯作者: van Batenburg-Sherwood, Joseph

siRNA targeting Schlemm's canal endothelial tight junctions enhances outflow facility and reduces IOP in a steroid-induced OHT rodent model.

• DOI: 10.1016/j.omtm.2020.10.022
• 发表时间: 2021-03-12
• 期刊: Molecular therapy. Methods & clinical development
• 作者: Cassidy PS;Kelly RA;Reina-Torres E;Sherwood JM;Humphries MM;Kiang AS;Farrar GJ;O'Brien C;Campbell M;Stamer WD;Overby DR;Humphries P;O'Callaghan J
• 通讯作者: O'Callaghan J

Reduced humidity experienced by mice in vivo coincides with reduced outflow facility measured ex vivo.

• DOI: 10.1016/j.exer.2019.107745
• 发表时间: 2019-09
• 期刊: Experimental eye research
• 影响因子: 3.4
• 作者: Ester Reina-Torres;Jacques A. Bertrand;Jeffrey O'Callaghan;J. Sherwood;P. Humphries;D. Overby

Unconventional aqueous humor outflow: A review.

• DOI: 10.1016/j.exer.2016.01.017
• 发表时间: 2017-05
• 期刊: Experimental eye research
• 影响因子: 3.4
• 作者: Johnson M;McLaren JW;Overby DR
• 通讯作者: Overby DR

Animal models of glucocorticoid-induced glaucoma.

• DOI: 10.1016/j.exer.2015.06.002
• 发表时间: 2015-12
• 期刊: Experimental eye research
• 影响因子: 3.4
• 作者: Overby DR;Clark AF
• 通讯作者: Clark AF