Telomere maintenance during anterior regeneration and aging in the freshwater annelid Aeolosoma viride

Chi-Fan Chen,Liuh-Yow Chen,Tzu-Ling Sung,Jiun-Hong Chen

doi:10.1038/s41598-018-36396-y

Chi-Fan Chen, Liuh-Yow Chen + Show 2 more

Open Access

https://doi.org/10.1038/s41598-018-36396-y

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Abstract

Aging is a complex process involving declines in various cellular and physical functionalities, including regenerative ability. Telomere maintenance is thought to be necessary for regeneration, and telomere attrition is one mechanism that contributes to aging. However, it is unclear if aging affects regeneration owing to deterioration of telomeric maintenance. We introduce Aeolosoma viride—a freshwater annelid with strong regenerative abilities—as a new model for studying the effects of aging on telomere functions and regeneration. We show that the anterior regenerative ability of A. viride declines with age. We characterized the A. viride telomere sequence as being composed of TTAGGG repeats and identifyied the telomerase gene Avi-tert. In adult A. viride, telomerase was constantly active and telomere lengths were similar among different body sections and stably maintained with age. Notably, we found that regeneration did not result in telomere shortening at regenerating sites. Moreover, transient up-regulation of Avi-tert expression and telomerase activity was observed at regenerating sites, which might promote telomere lengthening to counteract telomere erosion resulting from cell proliferation. Our study suggests that although aging affects A. viride regeneration independent of steady-state telomere length, timely regulation of telomerase functions is critical for the regeneration process in A. viride.

Highlights

Aging is a complex process involving declines in various cellular and physical functionalities, including regenerative ability
A. viride is able to regenerate different body parts, we chose to study head regeneration because in an intact worm the head region shows relatively low levels of cell proliferation compared to the tail region, which contains reproductive systems that could complicate our investigation of the regeneration process
~35% in the 6-weeks-old group did not survive (Fig. 1c). These results indicate that the regenerative ability of the anterior region of A. viride declines with age

Summary

Introduction

Aging is a complex process involving declines in various cellular and physical functionalities, including regenerative ability. In adult A. viride, telomerase was constantly active and telomere lengths were similar among different body sections and stably maintained with age. Transient up-regulation of Avi-tert expression and telomerase activity was observed at regenerating sites, which might promote telomere lengthening to counteract telomere erosion resulting from cell proliferation. Our study suggests that aging affects A. viride regeneration independent of steady-state telomere length, timely regulation of telomerase functions is critical for the regeneration process in A. viride. Planarians have high regeneration capacity that can regenerate their entire body from a tiny fragment using pluripotent stem cells[4]. The regenerative abilities of mammals mainly rely on tissue-specific stem cells, which exhibit age-dependent functional declines[9,15]. TERC assists in the assembly of telomerase and serves as a template for TERT to synthesize

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