Study Notes on Transcriptomic Effects of Spaceflight on Mouse Heart

Citation

  • Veliz, A.L. et al. (2023). "Transcriptomic Effects on the Mouse Heart Following 30 Days on the International Space Station." Biomolecules, 13, 371.

Abstract

  • Study investigates the impact of 30 days in space on the heart of female C57BL/6J mice.
  • 1147 transcripts significantly regulated after spaceflight; MAPK, PI3K-Akt, and GPCR pathways activated.
  • Upregulation of cytoskeleton-related transcripts; no significant change in ECM components or oxidative stress transcripts.
  • Indicates an adaptive cardiovascular response to prolonged spaceflight.

Introduction

  • Spaceflight affects multiple organ systems, particularly cardiovascular changes.
  • Previous studies focus on gene expression changes but limited data on prolonged effects on mouse hearts.
  • Need for understanding the transcriptomic changes of the heart from long-term space exposure.

Materials and Methods

  • Mice: Female C57BL/6J, acclimatized before spaceflight.
  • RNA Extraction & Sequencing: Samples collected from ISS (3 mice) and ground controls. RNA quality assessed before sequencing.
  • Data Analysis: Utilized StringTie and DESeq for expression profiling, focusing on significant changes (p < 0.05).

Results

Cardiac Transcriptome Changes

  • Significant alterations in signaling pathways affecting cell survival and cytoskeletal organization observed.
  • Downregulation in cAMP signaling and several markers related to cardiac function.

MAPK Signaling Activation

  • Activation of ERK/MAPK signaling pathway observed, promoting growth, differentiation, and survival in space conditions.
  • Induction of 23 transcripts associated with MAPK pathway regulatory functions.

Cytoskeleton and ECM

  • Altered cytoskeleton organization with significant dysregulation; however, ECM transcripts showed minimal change, suggesting structural integrity was largely maintained.

PI3K-Akt Pathway Activation

  • PI3K-Akt pathway significantly impacted, promoting cellular survival and adaptability.
  • Significant fold changes in key regulatory genes promoting cell-cycle progression.

Cellular Senescence

  • Lack of significant elevation of transcripts associated with cellular senescence; suggests adaptation and survival mechanisms prevail without promoting senescence.

Oxidative Stress Findings

  • Transcripts linked to oxidative stress largely unchanged; only seven out of 126 genes significantly altered, indicating oxidative stress was not a major impact factor.

Discussion

  • Findings suggest heart adaptation to the unique stresses of spaceflight, including potential enhancement in cellular maintenance pathways.
  • Highlight the necessity for studying longer durations and mixed-sex models for better understanding physiological responses to microgravity.
  • Proposes potential mechanisms through which prolonged exposure allows adaptation without significant oxidative damage or cellular senescence.