A lncRNA-encoded mitochondrial micropeptide exacerbates microglia-mediated neuroinflammation in retinal

Xintong Zheng1, Mingwei Wang1, Shuting Liu1

  • 1State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China.

Cell Death & Disease
|February 15, 2023
PubMed

Insights

Researchers identified a novel long noncoding RNA (181-Rik) and its micropeptide (Stmp1) involved in retinal ischemia/reperfusion injury. Targeting this pathway may offer new treatments for neurodegenerative eye diseases.

Area of Science:

  • Ophthalmology
  • Neuroscience
  • Molecular Biology

Background:

  • Retinal ischemia/reperfusion (IR) injury, common in diabetic retinopathy and glaucoma, causes inflammation and microglia activation, leading to irreversible vision loss.
  • The precise molecular mechanisms driving retinal IR injury remain largely unknown.
  • Microglia activation and inflammasome pathways are implicated in the pathogenesis of retinal IR.

Purpose of the Study:

  • To elucidate the molecular mechanisms of retinal IR injury.
  • To identify novel molecular targets for therapeutic intervention in IR-associated ocular disorders.

Main Methods:

  • Bioinformatic identification of long noncoding RNAs (lncRNAs) and micropeptides.
  • Genetic knockout and knockdown studies in mice and primary microglia.
  • Assessment of mitochondrial function, including fusion, membrane potential, and reactive oxygen species (ROS) production.
  • Analysis of inflammatory markers and inflammasome pathway activation (Nlrp3 inflammasome).
  • Evaluation of metabolic changes, specifically aerobic glycolysis.

Main Results:

  • A lncRNA, 1810058I24Rik (181-Rik), was identified, encoding a mitochondrion-located micropeptide, Stmp1.
  • Mice deficient in 181-Rik showed protection of retinal ganglion cells from IR injury, with reduced microglia activation and Nlrp3 inflammasome activity.
  • Genetic knockout of 181-Rik or its knockdown in microglia improved mitochondrial function, reduced ROS production and inflammation, and diminished aerobic glycolysis.
  • 181-Rik appears to activate Nlrp3 inflammasome by modulating mitochondrial function, inhibiting uncoupling protein 2 (Ucp2), and activating S100a8/a9 expression.

Conclusions:

  • 181-Rik and its micropeptide Stmp1 play a critical role in the molecular pathogenesis of retinal IR injury.
  • The 181-Rik/Stmp1 axis influences mitochondrial function and inflammatory responses, contributing to retinal damage.
  • Targeting the 181-Rik pathway presents a potential therapeutic strategy for neurodegenerative diseases associated with retinal IR.