The molecular mechanisms of collagen VIII-dependent gender differences in the development of diabetic nephropathy

《自然》杂志2010年第465期发表了一系列评论和文章，敦促将性别问题纳入议程。到目前为止，生物医学研究主要集中在男性试验对象上，而对女性不利，在许多情况下，将男性数据转移到女性体内的直接推断可能是完全错误的。几十年来，两性之间的差异以及他们对疾病的不同易感性是众所周知的。这些性别差异也被描述为糖尿病肾病(DN)，糖尿病的主要晚期后遗症。到目前为止，只有少数研究探讨性别效应的分子原因，换言之，评估性激素对糖尿病肾病的影响。糖尿病肾病的病理生理机制非常复杂，但目前对其发生发展的多种机制已有认识。在我们对糖尿病肾病的研究范围内，我们重点研究了基质蛋白VIII型胶原(COL8)。糖尿病肾病患者肾脏中COL8含量明显升高，提示COL8可能在糖尿病肾病的病理生理过程中发挥作用。对Col8基因敲除小鼠的后续动物研究证实了这些数据：与携带Col8野生型等位基因的糖尿病小鼠相比，没有Col8基因表达(基因敲除)的1型糖尿病小鼠的糖尿病肾病表现显著减少。在这些分析中，我们只使用雄性动物，以避免月经周期的干扰。下一步是研究在2型糖尿病引起的糖尿病肾病中，Col8基因敲除是否也具有肾脏保护作用。在这些实验中，我们比较了雄性和雌性动物。有趣的是，雌性Col8基因敲除小鼠并没有受到糖尿病肾病进展的保护。相反，与糖尿病野生型雌性和雄性小鼠相比，没有Col8的糖尿病雌性小鼠表现出糖尿病肾病的加重特征。对已经发表的一小部分糖尿病肾病患者队列数据的重新评估证实了这些发现。当前项目的目的将是调查导致依赖Col8的性别对糖尿病肾病的影响的机制。为此，我们将进行动物实验并分析患者的生物材料。为了确定分子机制，我们将在两个合作的背景下进行磷酸蛋白质组和信号转导分析。值得注意的是，许多实验读数将在我们实验室开发的体外肾脏模型中进行评估。总之，我们的初步数据揭示了依赖于Col8的糖尿病肾病发生和进展的性别差异的可能的分子原理。除了概念上的进展，深入了解糖尿病肾病期间依赖于Col8的过程的机制，将有助于揭示人类病理中经常被忽视的致命方面的性别差异。

The Nature edition no. 465 in the year 2010 published a series of commentaries and articles urging to include the gender in the agenda. Until now the biomedical research has focused mainly on male test subjects in detriment of females and the straightforward extrapolation of transfer of the male data to the female organism is, in many cases, probably simply wrong. The differences between both genders together with their distinct susceptibility for diseases are known for decades. These sex differences are also described for diabetic nephropathy (DN), the prime late sequel of diabetes mellitus. Heretofore there are only a few studies investigating the molecular causes of the gender effects, in other words, assessing the influence of sexual hormones on DN. The pathophysiology of DN is very complex, but many mechanism of the development and progression of DN have been identified. Within the scope of our studies of DN we focused on the matrix protein collagen VIII (Col8). Col8 is very markedly increased in the kidney of patients with DN pointing to a possible pathophysiological function of Col8 in DN. Follow-up animal studies with Col8 knockout mice confirmed these data: type 1 diabetic mice without col8 expression (knockout) showed a significantly reduced manifestation of DN compared with the diabetic mice carrying the Col8 wildtype allele. In these analyses we used exclusively male animals animals in order to avoid interference by the menstrual cycle. The next step was to study whether the Col8 knockout is also renoprotective in the case of type 2 diabetes mellitus induced DN. In these experiments we compared male and female animals. Interestingly, female Col8 knockout mice were not protected from progression of DN. Quite the contrary, diabetic female mice without Col8 showed exacerbated features of DN compared to the diabetic wildtype female and male mice. These findings were confirmed by the reevaluation of already published data from a small patient cohort with DN.The aim of the current project will be to investigate the mechanisms that are responsible for the Col8-dependent gender effects on DN. For this purpose we will carry out animal experiments and analyse patient biomaterial. To identify the molecular mechanisms at play we will run phosphoproteomic and signal transduction analysis in the context of two cooperations. Of note, many of the experimental readouts will be assessed in an ex-vivo kidney model developed in our laboratory. In summary, our preliminary data reveal a possible, molecular principle of the gender differences in development and progression of DN dependent on Col8. Beyond the mere conceptual advances, gaining insight into the mechanisms of Col8-dependent processes during DN will shed light on the often fatally neglected aspect of gender differences in human pathologies.