Cyclic Nucleotide-Specific Optogenetics Highlights Compartmentalization of the Sperm Flagellum into cAMP Microdomains

Abstract

Inside the female genital tract, mammalian sperm undergo a maturation process called capacitation, which primes the sperm to navigate across the oviduct and fertilize the egg. Sperm capacitation and motility are controlled by 3′,5′-cyclic adenosine monophosphate (cAMP). Here, we show that optogenetics, the control of cellular signaling by genetically encoded light-activated proteins, allows to manipulate cAMP dynamics in sperm flagella and, thereby, sperm capacitation and motility by light. To this end, we used sperm that express the light-activated phosphodiesterase LAPD or the photo-activated adenylate cyclase bPAC. The control of cAMP by LAPD or bPAC combined with pharmacological interventions provides spatiotemporal precision and allows to probe the physiological function of cAMP compartmentalization in mammalian sperm.

Soluble adenylyl cyclase inhibition prevents human sperm functions essential for fertilization

“…4,5, video 1,4). Upon stimulation with bicarbonate, consistent with other mouse studies 26 , mouse and human sperm increased their overall beat frequency to greater than 35 and 25 Hz, respectively. These increases were spatially distinct between mouse and human.…”

The Emerging Roles of Axonemal Glutamylation in Regulation of Cilia Architecture and Functions

“…Along with studying microtubule dynamics, optogenetic systems have recently been used to study cilia and flagella. The cAMP level in primary cilia or flagella can be regulated by light-activated phosphodiesterase (LAPD), which therefore allows scientists to temporally manipulate sperm motility or to study the spatial aspect of cAMP signaling in primary cilia ( Raju et al, 2019 ; Hansen et al, 2020 ). In addition, with the Cry2/CIBN-based optogenetic method, scientists can spatiotemporally manipulate the level of phosphoinositide in primary cilia, which regulates eye pressure ( Prosseda et al, 2020 ).…”

Odorant and Taste Receptors in Sperm Chemotaxis and Cryopreservation: Roles and Implications in Sperm Capacitation, Motility and Fertility

“…This movement of sperm is due to mobilization of Ca 2+ from cytoplasm preceded by membrane channels activation [ 48 ]. Membrane channels participating in regulation of Ca 2+ movement in spermatic cell includes CatSper [ 49 , 50 ], cyclic nucleotide gated (CNG) [ 51 , 52 ], and calcium voltage-gated channels (CaV) [ 53 , 54 ]. These channels have been localized in head, mid piece, and more abundantly in tail region of human, pig, and other mammals’ sperm [ 55 , 56 , 57 ], which suggest capacitation and hypermotility are dependent on activation of these channels ( Table 1 ).…”