Molecular and cellular mechanisms of prevention of bone loss by beta blockers

摘要/摘要 自妇女健康倡议以来，绝经后骨质流失一直是一个悬而未决的临床问题 显示了激素替代疗法的风险。为了解决这个问题，一项使用β受体阻滞剂的临床试验 (BBS)最近获得了名为“Beta1--选择性阻断预防骨质疏松症”的资助。 绝经后骨丢失：一项随机对照试验“(R01 AG065154-A1)。虽然这场审判将评估 BBS的有效性和安全性对于这一适应症，关于其机制和最佳使用仍存在疑问 这一预防策略。已经观察到BB对骨结果的异质性影响，这可能是由于 对于药物遗传学，我们已经发现并验证了ADRB1和HDAC4中的药物遗传变体。 此外，治疗效果的机制仍存在争议。尽管之前对小鼠的研究 研究表明，BBS的有益骨骼作用是由于与B2-肾上腺素能受体的竞争结合 (B2-Ars)在成骨细胞上，许多人类研究发现B1选择性阻滞剂与更好的 骨骼的结果。此外，我们还发现miR-19a-3p，我们假设它以B1-AR为靶点 (ADRB1)与BB的使用和较高的骨矿密度(BMD)有关。我们还展示了一个 ADRB1变异中的药物遗传关联，这与miR-19a-3p的表达呈正相关。 在小鼠研究中，我们显示了BB治疗对破骨细胞的一种新的直接作用，这种作用不是由 成骨细胞信号。总而言之，我们的初步药物遗传学和microRNA结果强调了 除了B2-AR信号外，B1-AR在BB骨骼效应中的重要性，我们的小鼠研究表明 除通过成骨细胞的间接影响外，BB治疗对破骨细胞的直接影响。我们的中央 假设与治疗反应相关的遗传和微RNA(MiRNA)变量有助于 成骨细胞和破骨细胞中B1-AR和B2-AR信号通路的调控。我们将对此进行测试 假设通过以下特定目的：1)测量体内阿替洛尔治疗对分化的影响 在参与者来源的破骨细胞中，发现和验证阿替洛尔治疗的药物遗传学变体 反应，并表征其对成骨细胞和破骨细胞的功能影响。2)使用miRNA-seq 确定与治疗反应相关的循环miRNAs，并发现靶点和验证机制 在成骨细胞和破骨细胞中。我们建议使用参与者派生的样本严格执行这些目标 从前面提到的审判中。这项建议将使我们能够描述BB治疗的机制 对绝经后妇女骨骼的影响，并创造个性化的治疗模式。

Abstract/Summary Post-menopausal bone loss has been an unresolved clinical problem since the Women’s Health Initiative showed the risks of hormone replacement therapy. To address this issue, a clinical trial using beta blockers (BBs) to improve bone health has recently been funded entitled, “Beta1-selective blockade for prevention of postmenopausal bone loss: A randomized controlled trial” (R01 AG065154-A1). While this trial will evaluate the efficacy and safety of BBs for this indication, questions will remain about the mechanism and optimal use of this prevention strategy. Heterogeneity of BB effects on bone outcomes have been observed and may be due to pharmacogenetics, as we have discovered and validated pharmacogenetic variants in ADRB1 and HDAC4. Furthermore, the mechanisms of treatment effect remain controversial. Although previous mouse studies showed that the beneficial bone effects of BBs were due to competitive binding to B2-adrenergic receptors (B2-ARs) on osteoblasts, many human studies have found B1-selective blockers to be associated with better bone outcomes. In addition, we have discovered that miR-19a-3p, which we hypothesize to target B1-AR (ADRB1), is associated with BB use and higher bone mineral density (BMD). We also show a pharmacogenetic association in an ADRB1 variant, which is positively associated with miR-19a-3p expression. In mouse studies, we have shown a novel direct effect of BB treatment on osteoclasts that is not mediated by osteoblast signaling. In summary, our preliminary pharmacogenetic and microRNA results underscore the importance of B1-AR in addition to B2-AR signaling for BB bone effects, and our mouse studies show evidence of direct effects of BB treatment on osteoclasts in addition to indirect effects via osteoblasts. Our central hypothesis is that genetic and microRNA (miRNA) variables associated with treatment response contribute to modulation of B1-AR and B2-AR signaling pathways in osteoblasts and osteoclasts. We will test this hypothesis via the following specific aims: 1) Measure the effect of in vivo atenolol treatment on differentiation in participant-derived osteoclasts, discover and validate pharmacogenetic variants of atenolol treatment response, and characterize their functional effects on osteoblasts and osteoclasts. 2) Use miRNA-seq to identify circulating miRNAs associated with treatment response, and discover targets and validate mechanisms in osteoblasts and osteoclasts. We propose to rigorously perform these aims using participant-derived samples from the previously mentioned trial. This proposal will allow us to characterize the mechanisms of BB treatment effect on bone in post-menopausal women and to create personalized treatment models.