Modifying the extracellular matrix to prevent dry eye disease and age-related Meibomian gland dysfunction (ARMGD)

项目总结 干眼病(DED)的患病率在患有干眼症的普通人群中从5%到50%不等。 估计相关医疗费用为38亿美元。DED的症状包括疼痛、疲倦 和/或眼睛疼痛、畏光和视力模糊，这会导致工作效率下降和 生活质量。不幸的是，DED的治疗选择有限。临床研究表明，85%的总体 DED病例是由眉板腺功能障碍(MGD)引起的。随着人类和小鼠年龄的增长，他们的眉毛 腺体(MG)经历与年龄相关的变化，包括腺泡基底细胞增殖减少和萎缩， 而这些变化导致了年龄相关的MGD(ARMGD)。ARMGD的确切原因仍然难以捉摸， 这使得治疗方法的发展极具挑战性。 透明质酸(HA)是一种主要的胞外成分，它与大量的 形成调节主要生理功能的复杂大分子的分子，如 发展和干细胞规格。我们最近发表的工作表明，复合HA合成酶 (Has)-1和-3缺失小鼠，即Has1-/-；Has3-/-小鼠与年龄匹配的小鼠相比，MG增大 野生型(Wt)小鼠。我们的初步数据显示，Has1-/-；Has3-/-小鼠的MG在 而且，有趣的是，这些小鼠不会患上ARMGD。1岁时，有1-/-；有3-/- 小鼠的MG体积惊人地增加了4倍，脂肪产量总体增加了10倍， 与年龄匹配的wt小鼠相比。我们假设，血管内和周围HA表达的增加 Has1-/-；Has3-/-小鼠的MGS能够在衰老过程中维持存活的祖细胞，这反过来 防止ARMGD。本提案的具体目标1将描述WT的MG中的细胞外基质。 有1-/-；有3-/-小鼠，重点是HA基质的组成。本提案的具体目标2 将分析MG祖细胞和增殖细胞的分布，以确定Has1-MGs是如何 /-；有3-/-小鼠随着时间的推移而放大。这一目的还将表征meiburn的脂质成分，以及 验证增大的腺体是否可以预防DED。重要的是，尽管Has1-/-；Has3-/-小鼠缺少两个 负责HA生物合成的酶的异构体，它们上调第三个异构体(Has2)，并且，在 反过来，与wt小鼠相比，MGs及其周围的HA表达显著增加。 因此，我们还假设，增加Has2在MGs中的表达和HA的生物利用度可以 预防老龄Wt小鼠ARMGD。特定目标3将测试Has2过度表达和FDA批准 羟基磷灰石为基础的治疗方案，以增加羟基磷灰石的生物利用度内的睑板和MGs可以防止 体重小鼠的ARMGD。

Project summary The prevalence of dry eye disease (DED) ranges from ~5 to 50% of the general population with an estimated US$ 3.8 billion dollars in associated medical costs. Symptoms of DED include pain, fatigued and/or sore eyes, photophobia and blurred vision, which lead to a decrease in productivity and reduce the quality of life. Unfortunately, treatment options for DED are limited. Clinical studies suggest 85% of overall DED cases are caused by Meibomian gland dysfunction (MGD). As humans and mice age, their Meibomian glands (MGs) undergo age-related changes, including decreased acinar basal cell proliferation and atrophy, and these changes result in age related-MGD (ARMGD). The precise cause of ARMGD remains elusive, which makes the development of therapies extremely challenging. Hyaluronan (HA) is a major extracellular component that interacts and binds to a myriad of molecules forming complex macromolecules which regulate major physiological functions, such as development and stem cell specification. Our recently published work shows that compound HA synthase (Has)-1 and -3 null mice, namely Has1-/-;Has3-/- mice, have enlarged MGs when compared to age matched wild-type (wt) mice. Our preliminary data show that the MGs of Has1-/-;Has3-/- mice continue to increase in size throughout life, and, interestingly, these mice do not develop ARMGD. At 1 year of age, Has1-/-;Has3-/- mice have a striking 4-fold increase in MG volume and an overall 10-fold increase in lipid production, compared to age matched wt mice. We hypothesize that the increase in HA expression in and around the MGs of Has1-/-;Has3-/- mice is capable of maintaining viable progenitor cells as they age, which in turn prevents ARMGD. Specific aim 1 of this proposal will characterize the extracellular matrix in the MGs of wt and Has1-/-;Has3-/- mice with a focus on the composition of the HA matrix. Specific aim 2 of this proposal will analyze the distribution of MG progenitor and proliferating cells in order to identify how the MGs of Has1- /-;Has3-/- mice enlarge over time. This aim will also characterize the lipid composition of the meibum, and verify whether enlarged glands can prevent DED. Importantly, although Has1-/-;Has3-/- mice lack two isoforms of the enzyme responsible for HA biosynthesis, they up-regulate the third isoform (Has2), and, in turn, present a significant increase in HA expression in and around MGs when compared to wt mice. Therefore, we also hypothesize that increasing Has2 expression and HA bioavailability within MGs could prevent ARMGD in aged wt mice. Specific aim 3 will test whether Has2 overexpression and FDA approved HA-based treatment regimens to increase the bioavailability of HA within tarsal plates and MGs can prevent ARMGD in wt mice.