Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, U.S.A.
Department of Otolaryngology, State University of New York Upstate Medical University, Syracuse, New York, U.S.A.
Laryngoscope. 2020 Dec;130(12):E773-E781. doi: 10.1002/lary.28493. Epub 2020 Jan 6.
OBJECTIVES/HYPOTHESIS: Glutamine metabolism is a critical energy source for iatrogenic laryngotracheal stenosis (iLTS) scar fibroblasts, and glutaminase (GLS) is an essential enzyme converting glutamine to glutamate. We hypothesize that the GLS-specific inhibitor BPTES will block glutaminolysis and reduce iLTS scar fibroblast proliferation, collagen deposition, and fibroblast metabolism in vitro.
Test-tube Lab Research.
Immunohistochemistry of a cricotracheal resection (n = 1) and a normal airway specimen (n = 1) were assessed for GLS expression. GLS expression was assessed in brush biopsies of subglottic/tracheal fibrosis and normal airway from patients with iLTS (n = 6). Fibroblasts were isolated and cultured from biopsies of subglottic/tracheal fibrosis (n = 6). Fibroblast were treated with BPTES and BPTES + dimethyl α-ketoglutarate (DMK), an analogue of the downstream product of GLS. Fibroblast proliferation, gene expression, protein production, and metabolism were assessed in all treatment conditions and compared to control.
GLS was overexpressed in brush biopsies of iLTS scar specimens (P = .029) compared to normal controls. In vitro, BPTES inhibited iLTS scar fibroblast proliferation (P = .007), collagen I (Col I) (P < .0001), collagen III (P = .004), and α-smooth muscle actin (P = .0025) gene expression and protein production (P = .031). Metabolic analysis demonstrated that BPTES reduced glycolytic reserve (P = .007) but had no effects on mitochondrial oxidative phosphorylation. DMK rescued BPTES inhibition of Col I gene expression (P = .0018) and protein production (P = .021).
GLS is overexpressed in iLTS scar. Blockage of GLS with BPTES significantly inhibits iLTS scar fibroblasts proliferation and function, demonstrating a critical role for GLS in iLTS. Targeting GLS to inhibit glutaminolysis may be a successful strategy to reverse scar formation in the airway.
NA Laryngoscope, 2020.
目的/假设：谷氨酰胺代谢是医源性喉气管狭窄（iLTS）瘢痕成纤维细胞的关键能量来源，谷氨酰胺酶（GLS）是将谷氨酰胺转化为谷氨酸的必需酶。我们假设 GLS 特异性抑制剂 BPTES 将阻断谷氨酰胺分解，并减少体外 iLTS 瘢痕成纤维细胞的增殖、胶原沉积和成纤维细胞代谢。
试管实验室研究。
对 1 例环状软骨气管切开术（n = 1）和 1 例正常气道标本（n = 1）进行免疫组织化学评估，以评估 GLS 表达。在 iLTS 患者的声门下/气管纤维化和正常气道的刷活检中评估 GLS 表达（n = 6）。从声门下/气管纤维化活检中分离和培养成纤维细胞（n = 6）。用 BPTES 和 GLS 下游产物类似物二甲基 α-酮戊二酸（DMK）处理成纤维细胞。在所有处理条件下评估成纤维细胞增殖、基因表达、蛋白产生和代谢，并与对照进行比较。
与正常对照组相比，iLTS 瘢痕标本刷活检中 GLS 过度表达（P =.029）。在体外，BPTES 抑制 iLTS 瘢痕成纤维细胞增殖（P =.007）、I 型胶原（Col I）（P < .0001）、III 型胶原（P = .004）和 α-平滑肌肌动蛋白（P = .0025）基因表达和蛋白产生（P = .031）。代谢分析表明，BPTES 降低糖酵解储备（P = .007），但对线粒体氧化磷酸化无影响。DMK 挽救了 BPTES 对 Col I 基因表达（P = .0018）和蛋白产生（P = .021）的抑制作用。
GLS 在 iLTS 瘢痕中过度表达。用 BPTES 阻断 GLS 可显著抑制 iLTS 瘢痕成纤维细胞的增殖和功能，表明 GLS 在 iLTS 中起关键作用。靶向 GLS 抑制谷氨酰胺分解可能是逆转气道瘢痕形成的成功策略。
无 喉镜，2020 年。
