Ion Channels in Sperm Physiology and Male Fertility and Infertility

Abstract

Ion channels regulate the membrane potential and intracellular ionic concentration and thus serve a central role in various cellular processes. Several ion channels have been identified in the germ cells, including sperm, emphasizing their importance in male fertility and reproduction. The molecular mechanism of ion transport and the nature of the ion channels involved have begun to emerge only recently despite the fact that several ligand-gated and voltage-gated channels have been identified and localized on sperm. The presence of the sperm-associated cation channel (CatSper1-4) gene family, proton voltage-gated ion channel (Hv1), potassium voltage-gated ion channel (SLO3/KCNU1), sodium voltage-gated channel (NaV1.1-1.9), and the members of the transient receptor potential (TRP) channel family suggest an indispensable role for ion channels in sperm physiology and fertility potential. Ion channels are the key players in very important processes such as capacitation and the acrosome reaction, which are critical steps in sperm physiology preparing for fertilization. For example, CatSper, Hv1, SLO3, and TRP channel family members have been proposed to participate in the acrosome reaction, thereby making them most important for sperm fertility. Similarly, NaV channels could play a crucial role in noncapacitated sperm and in the initial capacitation steps. The role of ion channels seems indispensable for sperm fertility as evidenced by studies on animal models; however, the functional defects in infertile human males await further exploration. This article represents an update on the role of ion channels in sperm physiology, male fertility, and infertility.

Single nucleotide variant detection in Jaffrabadi buffalo (Bubalus bubalis) using high-throughput targeted sequencing

“…The present study provides evidence of its role in fertility as it was exclusively enriched in fertility subgroup samples. In infertility subgroup samples the majority of the GO categories enriched were associated with molecular functions such as ion, cation and gated channel activity, which surprisingly were reported to be associated with infertility in males (Shukla et al 2012). Furthermore, GO categories enriched in the high milk production sample were associated with biological processes such as metabolic and ion transport processes.…”

Asymmetry of parental origin in long QT syndrome: preferential maternal transmission of KCNQ1 variants linked to channel dysfunction

“…As KCNQ1 is expressed in numerous organs and in different types of cells, variants that alter myocardial repolarization might also have important effects in other tissues and at early stages of development such as fertilization in which ion channels are crucially important. 24 Differential co-assembly of KCNQ1 with single transmembrane KCNE β-subunits in different cell types gives rise to a variety of biophysical properties, thus endowing distinct physiological roles for KCNQ1-KCNEx complexes. 6,20,25 Some of them are well-known.…”

Thermosensitive ion channel TRPV1 is endogenously expressed in the sperm of a fresh water teleost fish (Labeo rohita) and regulates sperm motility

“…13,14 In addition to the internal factors, the Ca 2+ -signaling experienced by the sperm cells is directly modulated by the environment into which the sperms are released, thus affecting their survival and fertilizing ability. Sperm cells exhibit extreme selectivity and sensitivity towards proper environment, which promotes their survival, whereas slight changes in the environment is detrimental for these cells.…”

“…For example, sperm cells demonstrate extreme sensitivity for minute changes in pH, temperature, osmolarity of the media and presence of very low level of elements etc. [7][8][9][10][11][12][13][14][15] The Ca 2+ channels present in the sperm cells play an important role in these processes. 16 The Ca 2+ channels present in the sperm cells are potential molecular targets, which respond to several stimuli in order to modulate the intracellular Ca 2+ levels.…”