Cytokine Regulation of Photoreceptor Gene Expression

描述(由申请人提供)：本提案是对编号为NOT-OD-09-058的通知的回应，标题为：NIH宣布可为竞争性修订申请提供恢复法案资金。因此，本申请旨在修订目前获得资助的项目EY016459。神经细胞因子在预防或延缓神经退行性变方面显示出巨大的治疗潜力，包括那些导致视网膜色素变性和干性黄斑变性的退行性变。当基因突变或环境因素多样或未知时，白血病抑制因子(LIF)和睫状神经营养因子(CNTF)的广谱保护活性具有明显的治疗优势。由于这一优势，CNTF正在进行II期临床试验，以防止视网膜色素变性(RP)患者的光感受器细胞死亡。几乎所有的药物都有不想要的副作用，通常当药物的使用远远超过其治疗范围时，这些副作用就会显现出来。不幸的是，在高浓度时，CNTF和LIF会有不良的副作用，降低光感受器功能，从而潜在地限制了它们的治疗价值。LIF与CNTF不是同源的，但在功能上是相关的。我们的研究表明，在中等剂量下，LIF在5倍范围内具有保护作用而不会降低功能，因此建立了一个较大的治疗范围。在较高剂量下，LIF抑制功能。高浓度的功能抑制是未来治疗的障碍，可能会限制分子的用途。我们希望通过确定LIF诱导生存的机制与其抑制功能的机制来进一步提炼LIF的治疗价值。这将使我们能够开发新的治疗方法，在不抑制功能的情况下提供广谱保护。细胞内靶标的识别将为小分子的开发开辟道路，这些小分子可以用来取代笨重和不稳定的蛋白质。 公共卫生相关性：神经性细胞因子在预防或延缓神经退行性变方面显示出巨大的治疗潜力，包括那些导致视网膜色素变性和干性黄斑变性的退行性变。当引起疾病的基因突变或环境因素多样或未知时，睫状神经营养因子(CNTF)的广谱保护活性具有明显的治疗优势。由于这一优势，CNTF正在进行II期临床试验，以防止视网膜色素变性(RP)患者的光感受器细胞死亡。几乎所有的药物都有不想要的副作用，通常当药物的使用远远超过其治疗范围时，这些副作用就会显现出来。不幸的是，在高浓度的情况下，CNTF会有不必要的副作用，降低光感受器功能，从而潜在地限制其治疗价值。白血病抑制因子(LIF)与CNTF不是同源的，但在功能上有相关性。我们的研究表明，在5倍的剂量范围内，LIF在不降低光感受器功能的情况下提供了对细胞死亡的保护。然而，当LIF在高浓度应用时，在高浓度下对功能的抑制会导致严重的不良后果。预计这是未来治疗的障碍，并可能限制这种重要分子的用途。该项目的一个目标是通过确定LIF诱导生存的机制与其抑制功能的机制来进一步确定LIF的治疗价值。这一知识将使新疗法的开发成为可能，这种疗法将提供广谱保护，而不会抑制功能。细胞内靶标的识别将为小分子的开发开辟道路，这些小分子可以用来取代笨重和不稳定的蛋白质。我们和其他人已经确定STAT3是LIF下游的一个转录因子，需要保护。此次修订的具体目的是确定受LIF调控的基因，这些基因特别需要STAT3。这将确定LIF诱导保护的机制。我们在初步工作中确定的一个候选基因是PIM丝氨酸/茶氨酸激活酶家族的成员。我们将使用这些激酶的基因敲除小鼠来确定它们是否对LIF诱导的保护是必要的。

DESCRIPTION (provided by applicant): This proposal is made in response to notice number NOT-OD-09-058 entitled: NIH Announces the Availability of Recovery Act Funds for Competitive Revision Applications. This application is therefore intended to revise the currently funded project EY016459. Neurological cytokines have shown tremendous therapeutic potential for preventing or delaying neurodegenerations, including those causing retinitis pigmentosa and dry macular degeneration. The broad-spectrum protective activity of leukemia inhibitory factor (LIF) and ciliary neurotrophic factor (CNTF) have a clear therapeutic advantage when the genetic mutation or environmental factors are diverse or unknown. Because of this advantage, CNTF is in phase II clinical trials to prevent photoreceptor cell death in patients suffering from retinitis pigmentosa (RP). Almost all drugs have unwanted side effects, which are usually manifested when drugs are used well above their therapeutic range. Unfortunately, at high concentrations, CNTF and LIF have the unwanted side effect of reducing photoreceptor function thus potentially limiting their therapeutic value. LIF is not homologous to CNTF but is functionally related. Our studies have shown that at moderate doses LIF is protective without reducing function over a 5 fold range, thus establishing a large therapeutic range. At higher doses LIF inhibits function. The inhibition of function at high concentrations is an impediment to future therapies and may limit the usefulness of the molecules. We would like to further refine the therapeutic value of LIF by determining the mechanism by which LIF induces survival versus its mechanism for inhibiting function. This would allow us to develop new therapies which would give broad spectrum protection without inhibiting function. The identification of intracellular targets would open the pathway for the development of small molecules that can be used instead of bulky and labile proteins. PUBLIC HEALTH RELEVANCE: Neurological cytokines have shown tremendous therapeutic potential for preventing or delaying neurodegenerations, including those causing retinitis pigmentosa and dry macular degeneration. The broad- spectrum protective activity of ciliary neurotrophic factor (CNTF) has a clear therapeutic advantage when the genetic mutation or environmental factors causing the disease are diverse or unknown. Because of this advantage, CNTF is in phase II clinical trials to prevent photoreceptor cell death in patients suffering from retinitis pigmentosa (RP). Almost all drugs have unwanted side effects, which are usually manifested when drugs are used well above their therapeutic range. Unfortunately, at high concentrations, CNTF has the unwanted side effect of reducing photoreceptor function, thus potentially limiting its therapeutic value. Leukemia inhibitory factor (LIF) is not homologous to CNTF but is functionally related. Our studies have shown that LIF provides protection from cell death without reducing photoreceptor function over a 5-fold range of dosages. Nevertheless, the inhibition of function at high concentrations has resulted in severe adverse consequences when LIF is applied at high concentrations. It is anticipated that this is an impediment to future therapies and may limit the usefulness of this important molecule. One goal of this project is to further define the therapeutic value of LIF by determining the mechanism by which LIF induces survival versus its mechanism for inhibiting function. This knowledge would allow development of new therapies which would give broad spectrum protection without inhibiting function. The identification of intracellular targets would open the pathway for the development of small molecules that can be used instead of bulky and labile proteins. We and others have identified STAT3 as a transcription factor downstream of LIF that is required for protection. The specific aims of this revision are to identify genes regulated by LIF that specifically require STAT3. This will identify the mechanism by which LIF induces protection. One candidate gene that we have identified in preliminary work is a member of the PIM serine/theronine kinase family. We will use knockout mice for these kinases to determine if they are essential for LIF induced protection.