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Functional characterization of bitter-taste receptors expressed in mammalian testis

Jiang Xu1, Jie Cao, Naoko Iguchi

  • 1Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA.

Molecular Human Reproduction
|September 18, 2012
PubMed

Insights

Male germ cells express bitter-taste receptors (T2rs) that detect potentially toxic compounds. These receptors influence sperm function and fertilization by sensing chemicals in their environment.

Area of Science:

  • Reproductive biology
  • Molecular biology
  • Sensory neuroscience

Background:

  • Spermatogenesis and sperm maturation are influenced by internal and external factors.
  • The interaction of male germ cells with environmental elements, including toxins, is not well understood.

Purpose of the Study:

  • To investigate the presence and function of bitter-taste receptors (T2rs) in male germ cells.
  • To determine if T2rs in sperm play a role in sensing chemicals that may affect reproductive processes.

Main Methods:

  • In situ hybridization to detect Tas2r transcript expression in mouse seminiferous tubules.
  • Functional analysis of calcium signaling in response to bitter compounds in mouse spermatids and spermatozoa.
  • Utilizing bitter-tastant blockers and gene knockout of G protein subunit α-gustducin to assess T2r pathway involvement.

Main Results:

  • Bitter-taste receptors (T2rs) are expressed in mouse seminiferous tubules, specifically in postmeiotic germ cells.
  • Mouse spermatids and spermatozoa exhibit calcium increases in response to bitter compounds, with distinct profiles suggesting unique receptor subsets.
  • These calcium responses are dependent on T2r signaling, as evidenced by suppression with blockers and abolition in knockout models.

Conclusions:

  • Male germ cells possess functional T2r receptors, similar to their counterparts in taste buds and airways.
  • These receptors enable sperm to sense chemicals in their environment, potentially impacting sperm behavior and fertilization outcomes.
  • T2rs represent a novel mechanism for male germ cells to interact with and respond to their milieu.

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