Retinoic Acid Signaling in Spermatogenesis

Retinoic acid (RA), the active metabolite of vitamin A, is indispensable for the precise orchestration of sperm production within the testis. Synthesised from retinol via retinaldehyde dehydrogenases and degraded by CYP26 enzymes, RA levels oscillate in a rhythmic manner to coordinate the cycle of the seminiferous epithelium. Peaks of RA drive undifferentiated spermatogonia to enter the differentiation pathway, initiate meiosis through upregulation of factors such as STRA8, and subsequently guide spermiogenesis, the maturation of haploid spermatids into spermatozoa. This multi-step control is mediated by nuclear retinoic acid receptors (RARs) and retinoid X receptors (RXRs), which regulate gene networks governing cell-cycle progression, chromatin remodelling and cytoskeletal remodelling. Aberrant RA signalling—whether through genetic disruption of synthetic enzymes, nutritional deficiency or environmental insults—can arrest spermatogenesis, contributing to male subfertility. Insights into RA dynamics have global implications, offering avenues for novel non-hormonal contraceptives and therapeutic strategies to restore male fertility.

Research from Nature Portfolio

Recent studies have revealed that multigenerational paternal obesity in mice leads to a progressive decline in testicular RA levels, impairing spermatogenesis in offspring. This effect is linked to downregulation of the WT1 transcription factor, which governs RA-synthesising enzymes, and to enhanced N6-methyladenosine modification of WT1 mRNA mediated by the METTL3 methyltransferase. Rescue experiments restoring WT1 expression or inhibiting METTL3 reinstated normal RA concentrations and sperm counts. A parallel study in human donors demonstrated elevated sperm N6-methyladenosine and reduced sperm concentration in overweight individuals, underscoring the transgenerational impact of metabolic status on RA-dependent germ cell development.

Retinoic Acid Signaling in Spermatogenesis publication trend

The graph below shows the total number of articles in retinoic acid signaling in spermatogenesis across all publications each year (not limited to Nature Index journals).

Technical terms

Retinoic acid (RA): The bioactive derivative of vitamin A that regulates gene expression in germ cells.

Spermatogonia: Undifferentiated male germ cells that divide and either self-renew or commit to differentiation.

Meiosis: Specialised cell division producing haploid gametes from diploid precursors.

Spermiogenesis: Final phase of spermatogenesis during which spermatids undergo morphological maturation into spermatozoa.

N6-methyladenosine (m6A): A reversible methyl modification on RNA influencing transcript stability and translation.

Transcription factor WT1: A DNA-binding protein that regulates expression of genes critical for RA synthesis.

METTL3: An RNA methyltransferase enzyme that installs m6A marks on target transcripts.

References

1. Multigenerational paternal obesity enhances the susceptibility to male subfertility in offspring via Wt1 N6-methyladenosine modification. Nature Communications (2024).
2. The Role of Retinoic Acid in Spermatogenesis and Its Application in Male Reproduction. Cells (2024).
3. Retinoic acid is dispensable for meiotic initiation but required for spermiogenesis in the mammalian testis. Development (2023).
4. Cycles, waves, and pulses: Retinoic acid and the organization of spermatogenesis. Andrology (2019).