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Elife. 2017 Jun 27;6. pii: e24888. doi: 10.7554/eLife.24888.

Semen amyloids participate in spermatozoa selection and clearance.

Author information

1
Department or Urology, University of California San Francisco, San Francisco, United States.
2
Gladstone Institute of Virology and Immunology, University of California San Francisco, San Francisco, United States.
3
Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany.
4
Kinderwunsch-Zentrum, Ulm, Germany.
5
The Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, Harvard Medical School, Boston, United States.
6
Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, United States.
7
Core Facility Functional Peptidomics, Ulm University, Ulm, Germany.
8
Department of Medicine, University of California San Francisco, San Francisco, United States.
9
Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, United States.
10
HIV / AIDS Division, San Francisco General Hospital, University of California San Francisco, San Francisco, United States.
11
Core Facility Transgenic Mice, Medical Faculty, Ulm University, Ulm, Germany.
12
Department of Microbiology and Immunology, University of California, San Francisco, United States.

Abstract

Unlike other human biological fluids, semen contains multiple types of amyloid fibrils in the absence of disease. These fibrils enhance HIV infection by promoting viral fusion to cellular targets, but their natural function remained unknown. The similarities shared between HIV fusion to host cell and sperm fusion to oocyte led us to examine whether these fibrils promote fertilization. Surprisingly, the fibrils inhibited fertilization by immobilizing sperm. Interestingly, however, this immobilization facilitated uptake and clearance of sperm by macrophages, which are known to infiltrate the female reproductive tract (FRT) following semen exposure. In the presence of semen fibrils, damaged and apoptotic sperm were more rapidly phagocytosed than healthy ones, suggesting that deposition of semen fibrils in the lower FRT facilitates clearance of poor-quality sperm. Our findings suggest that amyloid fibrils in semen may play a role in reproduction by participating in sperm selection and facilitating the rapid removal of sperm antigens.

KEYWORDS:

Amyloid; Reproduction; Semen; biophysics; human; human biology; medicine; structural biology

PMID:
28653619
PMCID:
PMC5487211
DOI:
10.7554/eLife.24888
[Indexed for MEDLINE]
Free PMC Article

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