Cyclerion Therapeutics, 245 First St., Riverview II, 18th Floor, Cambridge, MA, 02142, USA.
Ironwood Pharmaceuticals, Cambridge, MA, 02142, USA.
J Neuroinflammation. 2021 Sep 18;18(1):213. doi: 10.1186/s12974-021-02275-z.
Inflammation in the central nervous system (CNS) is observed in many neurological disorders. Nitric oxide-soluble guanylate cyclase-cyclic guanosine monophosphate (NO-sGC-cGMP) signaling plays an essential role in modulating neuroinflammation. CYR119 is a CNS-penetrant sGC stimulator that amplifies endogenous NO-sGC-cGMP signaling. We evaluated target engagement and the effects of CYR119 on markers of neuroinflammation in vitro in mouse microglial cells and in vivo in quinolinic acid (QA)-induced and high-fat diet-induced rodent neuroinflammation models.
Target engagement was verified in human embryonic kidney (HEK) cells, rat primary neurons, mouse SIM-A9 cells, and in rats by measuring changes in cGMP and downstream targets of sGC signaling [phosphorylated vasodilator-stimulated phosphoprotein (pVASP), phosphorylated cAMP-response element binding (pCREB)]. In SIM-A9 cells stimulated with lipopolysaccharides (LPS), markers of inflammation were measured when cells were treated with or without CYR119. In rats, microinjections of QA and vehicle were administered into the right and left hemispheres of striatum, respectively, and then rats were dosed daily with either CYR119 (10 mg/kg) or vehicle for 7 days. The activation of microglia [ionized calcium binding adaptor molecule 1 (Iba1)] and astrocytes [glial fibrillary acidic protein (GFAP)] was measured by immunohistochemistry. Diet-induced obese (DIO) mice were treated daily with CYR119 (10 mg/kg) for 6 weeks, after which inflammatory genetic markers were analyzed in the prefrontal cortex.
In vitro, CYR119 synergized with exogenous NO to increase the production of cGMP in HEK cells and in primary rat neuronal cell cultures. In primary neurons, CYR119 stimulated sGC, resulting in accumulation of cGMP and phosphorylation of CREB, likely through the activation of protein kinase G (PKG). CYR119 attenuated LPS-induced elevation of interleukin 6 (IL-6) and tumor necrosis factor (TNF) in mouse microglial cells. Following oral dosing in rats, CYR119 crossed the blood-brain barrier (BBB) and stimulated an increase in cGMP levels in the cerebral spinal fluid (CSF). In addition, levels of proinflammatory markers associated with QA administration or high-fat diet feeding were lower in rodents treated with CYR119 than in those treated with vehicle.
These data suggest that sGC stimulation could provide neuroprotective effects by attenuating inflammatory responses in nonclinical models of neuroinflammation.
中枢神经系统（CNS）中的炎症存在于许多神经疾病中。一氧化氮可溶性鸟苷酸环化酶-环磷酸鸟苷（NO-sGC-cGMP）信号转导在调节神经炎症中起着至关重要的作用。CYR119 是一种可穿透中枢神经系统的 sGC 刺激剂，可放大内源性 NO-sGC-cGMP 信号转导。我们评估了 CYR119 在体外的小鼠小胶质细胞和体内的喹啉酸（QA）诱导和高脂肪饮食诱导的啮齿动物神经炎症模型中对神经炎症标志物的靶标结合和作用。
通过测量 cGMP 和 sGC 信号转导的下游靶标[磷酸化血管扩张刺激磷蛋白（pVASP），磷酸化 cAMP 反应元件结合（pCREB）]的变化，在人胚肾（HEK）细胞、大鼠原代神经元、小鼠 SIM-A9 细胞和大鼠中验证靶标结合。在 SIM-A9 细胞中用脂多糖（LPS）刺激后，当细胞用或不用 CYR119 处理时，测量炎症标志物。在 QA 和载体分别注入纹状体右侧和左侧的大鼠中，然后每天给大鼠施用 CYR119（10mg/kg）或载体 7 天。通过免疫组织化学测量小胶质细胞[离子钙结合接头分子 1（Iba1）]和星形胶质细胞[胶质纤维酸性蛋白（GFAP）]的激活。用 CYR119（10mg/kg）治疗饮食诱导肥胖（DIO）小鼠 6 周，然后分析前额叶皮质中的炎症遗传标志物。
体外，CYR119 与外源性 NO 协同作用增加 HEK 细胞和原代大鼠神经元培养物中 cGMP 的产生。在原代神经元中，CYR119 刺激 sGC，导致 cGMP 积累和 CREB 磷酸化，可能通过蛋白激酶 G（PKG）的激活。CYR119 减弱了 LPS 诱导的小鼠小胶质细胞中白细胞介素 6（IL-6）和肿瘤坏死因子（TNF）的升高。在大鼠口服给药后，CYR119 穿过血脑屏障（BBB）并刺激脑脊液（CSF）中 cGMP 水平升高。此外，与 QA 给药或高脂肪饮食喂养相关的促炎标志物在 CYR119 治疗的啮齿动物中低于载体治疗的啮齿动物。
这些数据表明，sGC 刺激可能通过减轻神经炎症的炎症反应，为神经炎症的非临床模型提供神经保护作用。
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