Impaired TRVP4-eNOS signaling in TM contributes to glaucoma

摘要 原发性开角型青光眼（POAG）是最常见的青光眼形式，可导致不可逆的视力 损失由于小梁网（TM）组织的功能障碍而导致的眼内压（IOP）升高是青光眼的标志。 POAG。然而，导致TM功能障碍和眼压升高的病理机制尚不清楚 明白TM具有通过感测眼内血流的变化来维持IOP稳态的内在能力。 房水（AH）。在这方面，我们最近表明，钙离子内流通过瞬时受体电位， TM中的香草素4离子通道（TRPV 4 TM通道）通过激活内皮一氧化氮降低IOP 一氧化氮合酶（eNOS）-NO信号转导。重要的是，我们发现TRPV 4 TM-eNOSTM信号转导受损， 肉瘤原代人TM细胞。本申请的主要目的是阐明病理性 在青光眼中损害TRPV 4 TM-eNOS ™信号传导的机制，并靶向它们以拯救TM 功能慢性内质网（ER）应激是TM功能障碍和IOP升高的关键因素 在青光眼中。在我们的初步研究中，我们观察到慢性内质网应激激活诱导型一氧化氮合酶（iNOS）， 通常与氧化剂分子过氧亚硝酸盐（PN）的形成有关的酶。PN水平升高 在POAG供体眼的TM组织中，外源性PN降低了人原发性青光眼中TRPV 4 TM通道的活性。 TM细胞。此外，ER应激的诱导也降低了TRPV 4 TM通道的活性。因此，我们假设 PN诱导的TRPV 4 TM-eNOSTM信号传导抑制有助于TM功能障碍和IOP 青光眼的发病率本申请的主要目的是确定慢性内质网应激是否 在青光眼中通过PN诱导的TRPV 4 TM-eNOSTM信号转导的降低导致TM功能障碍和IOP升高， 并针对这种病理用于治疗青光眼。在目标1中，我们将确定慢性内质网应激是否 降低TM细胞中TRPV 4通道活性。在目标2中，我们将确定PN水平是否升高， 青光眼和PN是否降低TM中TRPV 4通道活性。我们还将确定慢性ER是否 压力是青光眼中PN水平升高的基础。在目标3中，我们将针对PN病理学降低IOP升高， 小鼠和人类高眼压模型。该提案利用佐德博士的互补专业知识， Sonkusare博士的TRP离子通道成像实验室， 电生理学本研究将利用最先进的钙离子成像、膜片钳、eNOS活性和一氧化氮 在原代人TM细胞和TM组织、人灌注培养的供体眼睛和小鼠中的测量 青光眼模型。成功完成拟议的研究将提供新的病理机制 和治疗一般POAG的治疗靶点。

Abstract Primary Open Angle Glaucoma (POAG) is the most common form of glaucoma that leads to irreversible vision loss. Elevated intraocular pressure (IOP) due to dysfunction of trabecular meshwork (TM) tissue is a hallmark of POAG. However, the pathological mechanisms leading to TM dysfunction and IOP elevation are poorly understood. TM has an intrinsic ability to maintain IOP homeostasis by sensing the changes in the flow of aqueous humor (AH). In this regard, we recently showed that Ca2+ influx through transient receptor potential vanilloid 4 ion channels in the TM (TRPV4TM channels) lowers IOP via activation of endothelial nitric oxide synthase (eNOS)–NO signaling. Importantly, we showed that TRPV4TM-eNOSTM signaling is impaired in glaucomatous primary human TM cells. The major goals of this application are to elucidate the pathological mechanisms that impair TRPV4TM-eNOSTM signaling in glaucoma and to target them for rescuing the TM function. Chronic endoplasmic reticulum (ER) stress is a crucial contributor to TM dysfunction and IOP elevation in glaucoma. In our preliminary studies, we observed that chronic ER stress activates inducible NOS (iNOS), an enzyme commonly associated with the formation of oxidant molecule peroxynitrite (PN). PN levels are elevated in TM tissues from POAG donor eyes and exogenous PN reduced TRPV4TM channel activity in human primary TM cells. Moreover, induction of ER stress also lowered TRPV4TM channel activity. Therefore, we hypothesize that PN-induced inhibition of TRPV4TM-eNOSTM signaling contributes to TM dysfunction and IOP elevation in glaucoma. The major objectives of this application are to determine whether chronic ER stress leads to TM dysfunction and IOP elevation via PN-induced lowering of TRPV4TM-eNOSTM signaling in glaucoma, and to target this pathology for the treatment of glaucoma. In Aim 1, we will determine whether chronic ER stress lowers TRPV4 channel activity in TM cells. In Aim 2, we will determine whether PN levels are elevated in glaucoma and whether PN lowers TRPV4 channel activity in TM. We will also determine whether chronic ER stress underlies elevated PN levels in glaucoma. In Aim 3, we will target PN pathology to lower elevated IOP in mouse and human models of ocular hypertension. This proposal utilizes complementary expertise of Dr. Zode’s laboratory in glaucoma research and ER stress, and Dr. Sonkusare’s laboratory in TRP ion channel imaging and electrophysiology. This study will utilize state-of-art Ca2+ imaging, patch-clamp, eNOS activity, and nitric oxide measurements in primary human TM cells and TM tissues, human perfusion cultured donor eyes, and mouse models of glaucoma. Successful completion of the proposed studies will provide novel pathological mechanisms and therapeutic targets for the treatment of general POAG.