Department of Pathophysiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, 116044, Liaoning, People's Republic of China.
Liaoning Provincial Key Laboratory of Medical Cellular and Molecular Biology, Dalian Medical University, Dalian, 116044, Liaoning, People's Republic of China.
Cell Mol Biol Lett. 2024 Sep 27;29(1):125. doi: 10.1186/s11658-024-00638-x.
Patients with tuberous sclerosis complex (TSC) develop renal cysts and/or angiomyolipomas (AMLs) due to inactive mutations of either TSC1 or TSC2 and consequential mTOR hyperactivation. The molecular events between activated mTOR and renal cysts/AMLs are still largely unknown.
The mouse model of TSC-associated renal cysts were constructed by knocking out Tsc2 specifically in renal tubules (Tsc2; ksp-Cre). We further globally deleted PRAS40 in these mice to investigate the role of PRAS40. Tsc2 cells were used as mTOR activation model cells. Inhibition of DNA methylation was used to increase miR-142-3p expression to examine the effects of miR-142-3p on PRAS40 expression and TSC-associated renal cysts.
PRAS40, a component of mTOR complex 1, was overexpressed in Tsc2-deleted cell lines and mouse kidneys (Tsc2; ksp-Cre), which was decreased by mTOR inhibition. mTOR stimulated PRAS40 expression through suppression of miR-142-3p expression. Unleashed PRAS40 was critical to the proliferation of Tsc2 cells and the renal cystogenesis of Tsc2; ksp-Cre mice. In contrast, inhibition of DNA methylation increased miR-142-3p expression, decreased PRAS40 expression, and hindered cell proliferation and renal cystogenesis.
Our data suggest that mTOR activation caused by TSC2 deletion increases PRAS40 expression through miR-142-3p repression. PRAS40 depletion or the pharmacological induction of miR-142-3p expression impaired TSC2 deficiency-associated renal cystogenesis. Therefore, harnessing mTOR/miR-142-3p/PRAS40 signaling cascade may mitigate hyperactivated mTOR-related diseases.
结节性硬化症（TSC）患者由于 TSC1 或 TSC2 的无活性突变以及随之而来的 mTOR 过度激活而发展出肾囊肿和/或血管平滑肌脂肪瘤（AML）。激活的 mTOR 与肾囊肿/AML 之间的分子事件在很大程度上仍不清楚。
通过特异性敲除肾小管中的 Tsc2（Tsc2; ksp-Cre）构建 TSC 相关肾囊肿的小鼠模型。我们进一步在这些小鼠中全局敲除 PRAS40 以研究 PRAS40 的作用。Tsc2 细胞被用作 mTOR 激活模型细胞。抑制 DNA 甲基化被用于增加 miR-142-3p 的表达，以研究 miR-142-3p 对 PRAS40 表达和 TSC 相关肾囊肿的影响。
PRAS40 是 mTOR 复合物 1 的一个组成部分，在 Tsc2 缺失的细胞系和小鼠肾脏（Tsc2; ksp-Cre）中过表达，这一表达被 mTOR 抑制所降低。mTOR 通过抑制 miR-142-3p 的表达来刺激 PRAS40 的表达。释放的 PRAS40 对于 Tsc2 细胞的增殖和 Tsc2; ksp-Cre 小鼠的肾囊肿形成至关重要。相比之下，抑制 DNA 甲基化会增加 miR-142-3p 的表达，降低 PRAS40 的表达，并阻碍细胞增殖和肾囊肿形成。
我们的数据表明，由 TSC2 缺失引起的 mTOR 激活通过抑制 miR-142-3p 来增加 PRAS40 的表达。PRAS40 的耗竭或 miR-142-3p 的药理学诱导表达损害了 TSC2 缺乏相关的肾囊肿形成。因此，利用 mTOR/miR-142-3p/PRAS40 信号级联可能减轻过度激活的 mTOR 相关疾病。
