Function of manchette and intra-manchette transport in spermatogenesis and male fertility

Abstract

The manchette is a transient skirt-like structure consisting of microtubules (MTs) and filamentous actin (F-actin) surrounding the elongating sperm head during spermiogenesis. It is pivotal in sperm head shaping controlled by the acrosome-acroplaxome-manchette complex, acrosome formation, and flagellar assembly by microtubular-based protein delivery. Defects in the manchette frequently lead to teratozoospermia concomitant with oligozoospermia and asthenozoospermia, but the pathogenic mechanism underlying manchette function and its role in male infertility remain poorly understood. In this review, we systematically described the assembly and disassembly of the manchette, intra-manchette transport (IMT) and its regulatory model, the function and mechanism of manchette and IMT in regulating sperm head shaping and flagellar assembly during spermatogenesis; summarized the research progress of manchette-related genes related to male infertility; and listed the manchette-related proteins in knockout mouse models and clinical cases, which provide the theoretical basis for an in-depth understanding of the molecular mechanism of manchette involved in spermatogenesis and male fertility for understanding the potentially developing treatments for infertility and reproductive disorders.

Keywords: AAM axis; IMT; Infertility; LINC complex; Manchette; Spermatogenesis.

Fig. 1

Pattern diagram of the manchette structure with its associated transport function and connectivity function structures. A An F-actin cytoskeletal pathway involving the myosin Va/Rab27a/b complex for short-distance transport. B An MT cytoskeletal pathway involving the kinesin/dynein for long-distance transport and MT ultrastructural pattern diagram. C An enlarged pattern diagram of the dense plaques at the end of the manchette. D A diagram of two special linkers of the nucleoskeleton and cytoskeleton (LINC) complexes. E A model diagram of nucleoplasmic transport and its LINC complex structure

Fig. 2

Model diagram of the mechanism of acroframosome-acroplaxome-manchette (AAM) axis regulating sperm head shaping. A The structure of the AAM axis. B The constriction proceeds of the AAM axis. C The hypothesis of the mechanism of manchette migration. IAM: Inner acrosomal membrane. NE: Nuclear endometrium

Fig. 3

Schematic diagram of protein transport systems during spermiogenesis. A A timeline to indicate the sequence of the three protein/vesicle transport pathways. B The multiple parallel cargo transport pathways and the precise location of some proteins in the flagella by IMT and IFT. C The formation of flagella and the main steps of IFT