全世界大約有10%人口受慢性腎臟病影響，對於其治療以及改善為當前重要的議題。慢性腎臟病會造成腎臟纖維化，其過程會失去腎臟細胞並且產生過量的細胞外基質（ECM）填補。已知腎臟上皮細胞經轉化生長因子-β刺激後，可以透過上皮間質轉化（EMT）作為腎臟纖維化的模型。 然而，代謝重整對於腎臟功能缺失是否影響仍是未知的。因此，我們嘗試探討腎臟上皮間質轉化以及代謝重整間的關係。在我們實驗室先前研究顯示，腎臟上皮細胞經轉化生長因子-β刺激，經上皮間質轉化後會有梭狀細胞型態、培養液酸化並且增加間質性細胞標記以及轉錄因子表現。接著我們利用液相層析儀/質譜儀分析代謝產物，結果顯示，腎臟上皮細胞經刺激形成間質特性細胞後改變代謝表現，其過程增加糖解作用、減少檸檬酸循環以及五碳糖磷酸途徑代謝產物。經海馬生物能量測定儀檢測，腎臟上皮細胞經刺激形成間質特性細胞增加糖解通量以及粒線體呼吸。此外，我們發現腎臟上皮經刺激形成間質特性細胞有特別的粒線體異常情況，粒線體膜間氫離子過極化、過氧化物堆積以及三磷酸腺苷（ATP）的減少。進一步，結果顯示腎臟上皮經刺激形成間質特性細胞會減少氧化還原能力以及增加氧化壓力。我們接著同時使用乳酸抑制劑草酸鈉以減少乳酸產生。結果顯示乳酸抑制劑草酸鈉減少轉化生長因子-β刺激造成的梭狀細胞型態、培養液酸化、間質性細胞標記於蛋白的表現，卻無法改變間質性細胞標記於信使核糖核酸（mRNA）的表現。草酸鈉減少轉化生長因子-β刺激造成的糖解通量。乳酸抑制劑草酸鈉減緩轉化生長因子-β刺激造成粒線體呼吸，但卻沒有減緩其他粒腺體異常的功能。乳酸抑制劑草酸鈉增加五碳糖磷酸途徑以及核酸合成代謝產物，但卻無法減緩轉化生長因子-β刺激造成減少氧化還原能力以及增加氧化壓力。我們的研究表示，腎臟經纖維化刺激後顯示有特別的代謝方式，並且調控代謝重整可以影響腎臟纖維化程度。

Around 10% of the population worldwide is affected by chronic kidney disease (CKD), the need for treatment and improvement becomes an important issue. CKD often results in kidney fibrosis, which is characterized by loss of renal cells and their replacement by extracellular matrix (ECM). Epithelial-to-mesenchymal transition (EMT) induced by transforming growth factor beta (TGFβ) family in renal tubular cells has been proposed as one of the models for kidney fibrosis. Recent studies show that kidney fibrosis is accompanied by metabolic reprogramming, altering the energy source from oxidative phosphorylation to glycolysis. However, whether metabolic reprogramming is causative for kidney functional loss remains unknown. Therefore, we attempted to study the interaction between metabolic reprogramming and renal EMT. Our results showed that TGFβ-induced mesenchymal signature exhibited a spindle-like morphology, media acidification, and upregulation of mesenchymal markers and transcription factors. By using LC/MS to determine the signal count of metabolites, we found that TGFβ-induced mesenchymal signature showed upregulation of glycolysis metabolites, downregulation of TCA cycle metabolites and associated amino acids, and decreased PPP metabolites and nucleotide synthesis. Seahorse analyzer confirmed increased glycolytic flux, but showed increased mitochondrial respiration as TGFβ-induced mesenchymal signatures. Surprisingly, we found that TGFβ-induced mesenchymal signature exhibited a special spectrum of mitochondrial dysfunction with hyperpolarization, increased mitochondrial ROS, but decreased ATP content. Moreover, TGFβ-induced mesenchymal signature exhibited decreased reducing power and increased oxidative stress. We next used lactate dehydrogenase A (LDHA) inhibitor sodium oxamate to inhibit lactate production. Although LDHA inhibition attenuated mesenchymal signature with decreased spindle-like morphology, media acidification, and downregulation of mesenchymal markers in protein levels, it did not reverse mesenchymal markers in mRNA levels. LDHA inhibition attenuated TGFβ-induced glycolytic flux in spite of upregulation of most glycolysis metabolites. LDHA inhibition reversed mitochondrial respiration, but did not rescue mitochondrial dysfunction induced by TGFβ. LDHA inhibition exhibited upregulated PPP metabolites and nucleotide synthesis, but did not reversed TGFβ-induced decreased reducing power and increased oxidative stress. Our study indicates that renal epithelial and TGFβ-induced mesenchymal signature exhibit a quite distinct metabolic program, and modulation of metabolism regulates the transition between them.

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