Journal Club: Beautiful microscopy study to show how Na+/K+-ATPase protein subunits differ depending on the cell type in Marmoset cochlea

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Today's journal article

Hosoya M, Ueno M, Shimanuki MN, Nishiyama T, Oishi N, Ozawa H. Cell-specific α and β subunit expression patterns of Na+/K+-ATPases in the common marmoset cochlea. 

Why I picked this article

The cochlea is highly dependent on ion homeostasis for normal function; maintaining high potassium concentration in a solution called "endolymph" in a compartment called the "scala media" acts as a battery to enable sensory hair cells to respond to sounds. Na⁺/K⁺-ATPase are proteins that function as active ion pumps, and are critical in maintaining this balance.  Loss of the function of those proteins can lead to permanent hearing loss. 

This study caught my attention because it investigates these ion pumps in common marmosets, a New World monkey and a common primate model used in biomedical research. Marmosets are genetically and developmentally much closer to humans than small animals like rodents. This research has investigated the Na⁺/K⁺-ATPase in the marmoset cochlea and compared it with previous research done in rodents, to better understand where and when these ion pumps play important roles in the primate cochlea. 

Some of the research findings

Animal model:
  • They examined neonatal and embryonic marmoset cochleae, looking at developmental stages.
  • Embryonic days (E) 96, E101, E109, E120, and at birth (postnatal day 0),
Na⁺/K⁺-ATPase protein targets: 
  • The team studied α-subunits (ATP1A1, ATP1A2, ATP1A3) and β-subunits (ATP1B1, ATP1B2, ATP1B3) of the Na⁺/K⁺-ATPase complex. Antibodies used were:
    • Anti-ATP1A1(a6F, DSHB & ab76020, Abcam)
    • Anti-ATP1A2(AB9094-I, Mrck KGaA)
    • Anti-ATP1A3(MA3-915, Invitrogen)
    • Anti-ATP1B1(ab2873, Abcam)
    • Anti-ATP1B2(PA5-26,279)
    • Anti-ATP1B3(11,142-1, Proteintech)
Finding: 
  • Na⁺/K⁺-ATPase proteins were found in spiral ganglion neurons (= auditory neurons), stria vascularis, and the organ of Corti of the marmoset cochlea. 
  • ATP1A3 and ATP1B1 were particularly enriched in spiral ganglion neurons. 
  • ATP1A1 and β-subunits appeared in regions involved in endolymph homeostasis, like the stria vascularis and marginal cells. 
  • Developmental changes in expression were observed. 
  • Interestingly, subunits identified were dependent on the cell type; it was different between type I and type II spiral ganglion cells, and between spiral ganglion neurons and glia. 
Figure 1b, auditory neurons in marmoset (at birth cochlea, with two Na⁺/K⁺-ATPase subunits (ATP1A1 and 3 as labelled in red and green). Hosoya et al. (2025)

Haruna's takeaway

This is another publication from the marmoset group, making a comparison between marmoset, rodent (previous research) and human (previous research, if available). It is very valuable to have translational studies to compare with primates, because by far the large majority of pre-clinical research to understand pathologies or new therapies involves the use of rodent animal models. 

I have kept the summary short for this publication, but immunohistochemistry is beautiful, and I would just recommend readers to access and read the original manuscript. Figure 9 summarises where and when you can find different protein subunits. 

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This is Haruna's 41/100 of the 100-day challenge to post a science blog article every day! I love inner ear biology & cochlear physiology.