Transcriptional and Proteomic Characterization of Telomere-Induced Senescence in a Human Alveolar Epithelial Cell Line

Daniel I Sullivan; Mao Jiang; Angela M Hinchie; Mark G Roth; Harinath Bahudhanapati; Mehdi Nouraie; Jie Liu; John F McDyer; Rama K Mallampalli; Yingze Zhang; Daniel J Kass; Toren Finkel; Jonathan K Alder

doi:10.3389/fmed.2021.600626

Transcriptional and Proteomic Characterization of Telomere-Induced Senescence in a Human Alveolar Epithelial Cell Line

Front Med (Lausanne). 2021 Feb 9:8:600626. doi: 10.3389/fmed.2021.600626. eCollection 2021.

Authors

Daniel I Sullivan^{1

2}, Mao Jiang^{1

3}, Angela M Hinchie¹, Mark G Roth¹, Harinath Bahudhanapati^{1

2}, Mehdi Nouraie^{1

2}, Jie Liu^{4

5

6}, John F McDyer¹, Rama K Mallampalli⁷, Yingze Zhang^{1

2}, Daniel J Kass^{1

2}, Toren Finkel^{4

5

6}, Jonathan K Alder^{1

2}

Affiliations

¹ Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, United States.
² Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, Pittsburgh, PA, United States.
³ The Third Xiangya Hospital, Central South University, Changsha, China.
⁴ Aging Institute, University of Pittsburgh, Pittsburgh, PA, United States.
⁵ University of Pittsburgh Medical Center, Pittsburgh, PA, United States.
⁶ Division of Cardiology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States.
⁷ Department of Internal Medicine, The Ohio State University, Columbus, OH, United States.

Abstract

Cellular senescence due to telomere dysfunction has been hypothesized to play a role in age-associated diseases including idiopathic pulmonary fibrosis (IPF). It has been postulated that paracrine mediators originating from senescent alveolar epithelia signal to surrounding mesenchymal cells and contribute to disease pathogenesis. However, murine models of telomere-induced alveolar epithelial senescence fail to display the canonical senescence-associated secretory phenotype (SASP) that is observed in senescent human cells. In an effort to understand human-specific responses to telomere dysfunction, we modeled telomere dysfunction-induced senescence in a human alveolar epithelial cell line. We hypothesized that this system would enable us to probe for differences in transcriptional and proteomic senescence pathways in vitro and to identify novel secreted protein (secretome) changes that potentially contribute to the pathogenesis of IPF. Following induction of telomere dysfunction, a robust senescence phenotype was observed. RNA-seq analysis of the senescent cells revealed the SASP and comparisons to previous murine data highlighted differences in response to telomere dysfunction. We conducted a proteomic analysis of the senescent cells using a novel biotin ligase capable of labeling secreted proteins. Candidate biomarkers selected from our transcriptional and secretome data were then evaluated in IPF and control patient plasma. Four novel proteins were found to be differentially expressed between the patient groups: stanniocalcin-1, contactin-1, tenascin C, and total inhibin. Our data show that human telomere-induced, alveolar epithelial senescence results in a transcriptional SASP that is distinct from that seen in analogous murine cells. Our findings suggest that studies in animal models should be carefully validated given the possibility of species-specific responses to telomere dysfunction. We also describe a pragmatic approach for the study of the consequences of telomere-induced alveolar epithelial cell senescence in humans.

Keywords: A549; IPF; SASP; aging; biomarker; mass spectrometry; secretome; telomerase.

Abstract

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