Targeting metabolic abnormalities to reverse fibrosis in iatrogenic laryngotracheal stenosis

Murphy, Michael; Motz, Kevin; Ding, Dacheng; Yin, Linda X.; Duvvuri, Madhavi; Feeley, M. M.; Hillel, Alexander T.

doi:10.1002/lary.26893

Cited by 12 publications

(26 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…20,[29][30][31] BPTES inhibition of GLS was effective at reducing fibroblast proliferation and collagen production and may be the principal reason why DON is effective to reverse iLTS. 14 Glycolysis is the preferred biosynthetic pathway for iLTS fibroblasts. 9 Metabolic inhibition by DON reduced both glycolysis and oxidative phosphorylation in iLTS scar fibroblasts.…”

Section: Discussionmentioning

confidence: 99%

“…Mito stress test and glycolysis stress test was performed the following day as per the manufacturer's protocol. 14…”

Section: Cellular Oxygen Consumption and Extracellular Acidification mentioning

confidence: 99%

“…14 Targeted therapies have been developed against glutamine metabolism, including inhibition of glutamine uptake and glutamine-catalyzed enzyme activity in cancer and pulmonary fibrosis. 12,[14][15][16][17] Blockade of the glutamine transporter ASCT2 with V-9302 resulted in attenuated cancer cell growth and proliferation. 18 In other studies, glutaminase (GLS) inhibition with DON (6-Diazo-5-oxo-Lnorleucine), compound 968, CB-839, and BPTES (bis-2-[5-phenylacetamido-1,2,4-thiadiazol-2-yl] ethyl sulfide) was effective at inhibiting tumor growth and treating idiopathic pulmonary fibrosis by reducing cell proliferation and collagen deposition.…”

Section: Introductionmentioning

confidence: 99%

“…To meet the increased metabolic demand, cells use glucose and glutamine for biogenesis 9,12–13 . Glutamine has been shown to be a critical amino acid for iLTS scar fibroblasts, and glutamine inhibition has been effective at reducing iLTS scar fibroblast proliferation and collagen deposition, as well as decreasing glycolysis and mitochondrial oxidative phosphorylation 14 …”

Section: Introductionmentioning

confidence: 99%

“…Targeted therapies have been developed against glutamine metabolism, including inhibition of glutamine uptake and glutamine‐catalyzed enzyme activity in cancer and pulmonary fibrosis 12,14–17 . Blockade of the glutamine transporter ASCT2 with V‐9302 resulted in attenuated cancer cell growth and proliferation 18 .…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Inhibition of glutaminase to reverse fibrosis in iatrogenic laryngotracheal stenosis

et al. 2020

Self Cite

View full text Add to dashboard Cite

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 GLSspecific inhibitor BPTES will block glutaminolysis and reduce iLTS scar fibroblast proliferation, collagen deposition, and fibroblast metabolism in vitro. Study Design: Test-tube Lab Research. Methods: 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. Results: 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). Conclusions: 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.

show abstract

Section: Discussionmentioning

confidence: 99%

“…Mito stress test and glycolysis stress test was performed the following day as per the manufacturer's protocol. 14…”

Section: Cellular Oxygen Consumption and Extracellular Acidification mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Inhibition of glutaminase to reverse fibrosis in iatrogenic laryngotracheal stenosis

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

M2 Macrophages Promote Collagen Expression and Synthesis in Laryngotracheal Stenosis Fibroblasts

et al. 2020

Self Cite

View full text Add to dashboard Cite

Objective Macrophages exhibit distinct phenotypes and are dysregulated in a model of iatrogenic laryngotracheal stenosis (iLTS). Increased populations of alternatively activated or M2 macrophages have been demonstrated. However, the role of these macrophages is unknown. The aims of this study are: 1) define the macrophage population in iLTS in the context of classically activated or M1 and M2 macrophage phenotypes, and 2) characterize the effect of monocyte‐derived M1 and M2 macrophages on normal airway and LTS‐derived fibroblasts (FBs) in vitro. Study Design Comparative analysis; in vitro controlled study. Methods Immunohistochemical analysis of human iLTS and control specimens was performed to define the macrophage population. In vitro, M1, and M2 macrophages were polarized using M‐CSF + Interferon‐gamma and lipopolysaccharide or Interleukin‐4, respectively. FBs isolated from laryngotracheal scar (LTS‐FBs) and normal tracheal airway (NA‐FBs) in eight patients with iLTS were cocultured with polarized macrophages. Fibrosis gene expression, soluble collagen production, and proliferation were assessed. Results Immunohistochemical analysis revealed increased CD11b + cells (macrophage marker) in laryngotracheal scar specimens (18.3% vs. 8.5%, P = .03) and predominant CD206 (M2) costaining versus CD86 (M1) (51.5% vs. 9.8%, n = 10, P = .001). In vitro, NA‐FBs cultured with M2 macrophages demonstrated a 2.41‐fold increase in collagen‐1 expression (P = .05, n = 8) and an increase in soluble collagen (9.98 vs. 8.875, mean difference: 1.11 95%, confidence interval 0.024–2.192, n = 8, P = .015). Conclusion Increased populations of CD11b cells are present in iLTS specimens and are predominantly CD206+, indicating an M2 phenotype. In vitro, M2 macrophages promoted collagen expression in airway FBs. Targeting macrophages may represent a therapeutic strategy for attenuating fibrosis in iLTS. Level of Evidence NA Laryngoscope, 131:E346–E353, 2021

show abstract

Characterization of Fibroblasts in Iatrogenic Laryngotracheal Stenosis and Type II Diabetes Mellitus

et al. 2020

Self Cite

View full text Add to dashboard Cite

Objectives Iatrogenic laryngotracheal stenosis (iLTS) is the pathological narrowing of the glottis, subglottis, and/or trachea due to scar tissue. Patients with type 2 diabetes mellitus (T2DM) are over 8 times more likely to develop iLTS and represent 26% to 53% of all iLTS patients. In this investigation, we compared iLTS scar‐derived fibroblasts in patients with and without T2DM. Study Design Controlled ex vivo study. Methods iLTS scar fibroblasts were isolated and cultured from subglottic scar biopsies in iLTS patients diagnosed with or without type 2 diabetes (non‐T2DM). Fibroblast proliferation, fibrosis‐related gene expression, and metabolic utilization of oxidative phosphorylation (OXPHOS) and glycolysis were assessed. Contractility was measured using a collagen‐based assay. Metabolically targeted drugs (metformin, phenformin, amobarbital) were tested, and changes in fibrosis‐related gene expression, collagen protein, and contractility were evaluated. Results Compared to non‐T2DM, T2DM iLTS scar fibroblasts had increased α‐smooth muscle actin (αSMA) expression (8.2× increased, P = .020), increased contractility (mean 71.4 ± 4.3% vs. 51.7 ± 16% Δ area × 90 minute−1, P = .016), and reduced proliferation (1.9× reduction at 5 days, P < .01). Collagen 1 (COL1) protein was significantly higher in the T2DM group (mean 2.06 ± 0.19 vs. 0.74 ±.44 COL1/total protein [pg/μg], P = .036). T2DM iLTS scar fibroblasts had increased measures of OXPHOS, including basal respiration (mean 86.7 vs. 31.5 pmol/minute/10 μg protein, P = .016) and adenosine triphosphate (ATP) generation (mean 97.5 vs. 25.7 pmol/minute/10 μg protein, P = .047) compared to non‐T2DM fibroblasts. Amobarbital reduced cellular contractility; decreased collagen protein; and decreased expression of αSMA, COL1, and fibronectin. Metformin and phenformin did not significantly affect fibrosis‐related gene expression. Conclusion T2DM iLTS scar fibroblasts demonstrate a myofibroblast phenotype and greater contractility compared to non‐T2DM. Their bioenergetic preference for OXPHOS drives their increased contractility, which is selectively targeted by amobarbital. Level of Evidence NA Laryngoscope, 131:1570–1577, 2021

show abstract

Targeting metabolic abnormalities to reverse fibrosis in iatrogenic laryngotracheal stenosis

Abstract: NA. Laryngoscope, 128:E59-E67, 2018.

Cited by 12 publications

References 33 publications

Inhibition of glutaminase to reverse fibrosis in iatrogenic laryngotracheal stenosis

Inhibition of glutaminase to reverse fibrosis in iatrogenic laryngotracheal stenosis

M2 Macrophages Promote Collagen Expression and Synthesis in Laryngotracheal Stenosis Fibroblasts

Characterization of Fibroblasts in Iatrogenic Laryngotracheal Stenosis and Type II Diabetes Mellitus

Contact Info

Product

Resources

About