Kidney proximal tubule (PT) cells have high-metabolic demands to drive the extraordinary ion and solute transport, water reabsorption, and endocytic uptake that occur in this nephron segment. Increases in renal blood flow alter glomerular filtration rate and lead to rapid mechanosensitive adaptations in PT transport, impacting metabolic demand. Although the PT reabsorbs essentially all of the filtered glucose, PT cells rely primarily on oxidative metabolism rather than glycolysis to meet their energy demands. We lack an understanding of how PT functions are impacted by changes in O2 availability via cortical capillaries and mechanosensitive signaling in response to alterations in luminal flow. Previously, we found that opossum kidney (OK) cells recapitulate key features of PT cells in vivo, including enhanced endocytic uptake and ion transport, when exposed to mechanical stimulation by culture on an orbital shaker. We hypothesized that increased oxygenation resulting from orbital shaking also contributes to this more physiologic phenotype. RNA seq of OK cells maintained under static conditions or exposed to orbital shaking for up to 96 hours showed significant time- and culture-dependent changes in gene expression. Transcriptional and metabolomics data were consistent with a decrease in glycolytic flux and with an increased utilization of aerobic metabolic pathways in cells exposed to orbital shaking. Moreover, we found spatial differences in the pattern of mitogenesis vs development of ion transport and endocytic capacities in our culture system that highlight the complexity of O2 -dependent and mechanosensitive crosstalk to regulate PT cell function.

中文翻译：

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剪应力和氧气可用性驱动负鼠肾近端小管细胞代谢和胞吞作用的差异性变化。

肾脏近端肾小管（PT）细胞具有高代谢要求，以驱动此肾单位段中发生的异常离子和溶质运输，水重吸收和内吞摄取。肾血流量的增加改变了肾小球的滤过率，并导致PT转运迅速发生机械敏感性适应，从而影响了代谢需求。尽管PT基本上吸收了所有过滤后的葡萄糖，但PT细胞主要依靠氧化代谢而不是糖酵解来满足其能量需求。我们缺乏对皮层毛细血管和机械敏感信号响应皮腔流量的氧气可利用性变化对PT功能的影响的理解。以前，我们发现负鼠肾（OK）细胞在体内概括了PT细胞的关键特征，包括增强的内吞摄取和离子转运，当在轨道振动台上受到培养物的机械刺激时。我们假设轨道震动引起的氧合增加也有助于这种更生理的表型。OK细胞的RNA seq保持在静态条件下或暴露于轨道振动长达96小时，显示出基因表达的明显时间依赖性和培养依赖性。转录和代谢组学数据与糖酵解通量的减少以及有氧代谢途径在暴露于眼眶震动的细胞中的利用增加是一致的。此外，我们在我们的培养系统中发现了有丝分裂发生模式与离子运输和内吞能力发展之间的空间差异，突显了O2依赖和机械敏感串扰调节PT细胞功能的复杂性。