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Updated: Apr 1, 2026
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Author Spotlight: Extended Oxygen Consumption Measurement in Retinal Pigment Epithelium Using Resipher
Published on: August 16, 2024
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Cell-Type-Dependent Metabolic Compensation Preserves Photoreceptor Survival Through Pyruvate Kinase Isoform Balance.
Ammaji Rajala1,2, Larissa J Trevino1,2, Tyler M Black1,2
1Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
Summary
Maintaining the balance of pyruvate kinase isoforms (PKM1 and PKM2) is crucial for photoreceptor survival. Insufficient compensation with PKM1 after PKM2 loss leads to retinal degeneration, while adequate compensation preserves vision.
Area of Science:
- Biochemistry
- Cell Biology
- Neuroscience
Background:
- Photoreceptors require aerobic glycolysis for outer segment renewal.
- Metabolic dysregulation contributes to retinal degeneration.
- The interplay of pyruvate kinase M2 (PKM2) and lactate dehydrogenase A (LDHA) in retinal homeostasis is unclear.
Purpose of the Study:
- To investigate the effects of deleting LDHA and PKM2 in retinal neurons.
- To understand the role of PKM isoform balance in photoreceptor survival.
Main Methods:
- Rod-specific deletion of LDHA and/or PKM2.
- Retinal-wide deletion of LDHA and PKM2.
- Translating ribosome affinity purification.
- Metabolic analyses.
Main Results:
- Rod-specific LDHA deletion, or combined LDHA/PKM2 deletion in rods, caused photoreceptor degeneration.
- Loss of LDHA reduced PKM2 and induced insufficient PKM1 compensation.
- Retinal-wide LDHA/PKM2 deletion led to robust PKM1 induction, preserving retinal structure and function.
- Non-rod neurons contribute to retinal lactate production.
Conclusions:
- A threshold model for PKM isoform balance determines retinal outcome.
- Sufficient PKM1 compensation for PKM2 loss preserves retinal integrity.
- Cell-type-dependent metabolic compensation and PKM isoform balance are key to photoreceptor survival.
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