Strictures of a microchannel impose fierce competition to select for highly motile sperm

Zaferani, Meisam; Palermo, Gianpiero D.; Abbaspourrad, Alireza

doi:10.1126/sciadv.aav2111

Cited by 67 publications

(45 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…differential capacitation or hyperactivation kinetics). Studying these aspects of the phenotype will require improved methods to separate sperm with differing motility and probe their biochemistry and chromosomal content, with recent advances in microfluidics providing a potential route forward [47]. This work adds to the growing body of experimental and theoretical work demonstrating that even in animal sperm that undergo postmeiotic transcriptional shutdown, haploid selection within a single ejaculate is an important and underappreciated evolutionary force [49][50][51][52][53][54].…”

Section: Discussionmentioning

confidence: 99%

“…This may be because performing the fractionation in a large volume measures increased diffusion via increased general motility, rather than progressive linear velocity. Another contributing factor is likely to be the absence of the various strictures in the female reproductive tract that select for highly motile versus weakly motile cells [47]. We note however that since the bottom, least motile fraction contains an equal proportion of X-and Y-bearing sperm, any contamination of the upper, more motile fractions necessarily serves to reduce the skew, and that our results are therefore a conservative measure of X / Y motility differences.…”

mentioning

confidence: 88%

See 1 more Smart Citation

Differential sperm motility mediates the sex ratio drive shaping mouse sex chromosome evolution

Rathje

Johnson

Drage

et al. 2019

Preprint

View full text Add to dashboard Cite

The search for morphological or physiological differences between X-and Y-bearing mammalian sperm has provoked controversy for decades. Many potential differences have been proposed, but none validated, while accumulating understanding of syncytial sperm development has cast doubt on whether such differences are possible even in principle. We present the first ever mammalian experimental model to trace a direct link from a measurable physiological difference between X-and Y-bearing sperm to the resulting skewed sex ratio. We show that in mice with deletions on chromosome Yq, birth sex ratio distortion is due to a relatively greater motility of X-bearing sperm, and not to any aspect of sperm/egg interaction. Moreover, the morphological distortion caused by Yq deletion is more severe in Y-bearing sperm, providing a potential hydrodynamic basis for the altered motility.This reinforces a growing body of work indicating that sperm haploid selection is an important and underappreciated evolutionary force.We thank the animal handling staff at

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 88%

Differential sperm motility mediates the sex ratio drive shaping mouse sex chromosome evolution

Rathje

Johnson

Drage

et al. 2019

Preprint

View full text Add to dashboard Cite

show abstract

“…In addition, these methods require a stringent skill set, lack standardized procedures, and prone to human errors (1), not to mention that they unfavorably are time consuming. However, new technologies with minimal perturbation, such as microfluidics, have been extensively explored and considered as promising remedies for the flaws associated with the conventional methods (2,7,(11)(12)(13)(14)(15).…”

Section: Figures 1 Tomentioning

confidence: 99%

Progressive Sperm Separation Using Parallelized, High-Throughput, Microchamber-based Microfluidics

Yaghoobi

Azizi

Mokhtare

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

Motility is one of the most important factors in sperm migration toward egg. Therefore, sperm separation based on motility increases the chance of the best sperm selection in the process of infertility treatments. Unfortunately, it is now vastly done by conventional procedures which lack certain delicacy and precision and increase the risk of damage to sperm cells. Microfluidic systems, on the other hand, can sort sperm in a less intrusive way. However, microfluidic techniques have yet to receive widespread adoption in clinical settings, not only due to their relatively cumbersome operation, but also their extremely low outcome, leaving them inefficient in practice. Here we propose a microchamber-based microfluidic platform that can separate progressive motile sperm from nonviable sperm and debris as well as trapped nonprogressive sperm in the microchambers. Our platform is operated in a short period of time (<10 min) with an excellent degree of controllability, without any prior sample preparation. Our results show that the microchambers depth does not affect the residence time of motile sperm. Therefore, we are able to inspect high sample volumes (1 mL) within the same time. Furthermore, we maximize the concentration of the collected sperm by tuning the washing medium flow rate above the sperm rheotactic threshold. We foresee that our microfluidic platform may provide a facile solution for high-throughput, robust, and easy-to-modify for collection of progressive sperm needed for assisted reproductive technologies (ARTs).

show abstract

“…Strikingly, the role of this chemical communication observed in marine invertebrate sperm (which is reminiscent of bacterial chemotaxis (14)) is uncertain in the navigation of mammalian sperm (13, 15–19). In contrast, in vitro/vivo evidence suggests that the navigation of mammalian sperm within the female reproductive tract depends more on fluid mechanical clues rather than other external stimuli (2, 7, 9, 20, 21).…”

Section: Introductionmentioning

confidence: 95%

“…However, boundary-dependent navigation that relies upon the hydrodynamic interactions of the swimmer with rigid walls, as well as self-propulsion and steric repulsion of sperm cells (25), is independent of the external flow and exists even in a quiescent medium. In fact, boundary-dependent navigation consists of a far-field hydrodynamic attraction of the sperm toward nearby walls (26–29), such as those of the female reproductive tract, followed by stably swimming along these boundaries (20, 21, 37, 22, 30–36). Berke et al (27) proposed a dipole swimmer model that describes the attraction of sperm as a microswimmer with absolute progressive motility toward rigid boundaries at distances far enough from the boundaries (i.e., the far-field approximation).…”

Section: Introductionmentioning

confidence: 99%

Effect of flagellar beating pattern on sperm rheotaxis and boundary-dependent navigation

Zaferani

Javi

Mokhtare

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

7The study of navigational mechanisms used by mammalian sperm inside a microenvironment 8 yields better understanding of sperm locomotion during the insemination process, which aids in 9 the design of tools for overcoming infertility. Near-and far-field hydrodynamic interactions with 10 nearby boundaries and rheotaxis are known to be some of the steering strategies that keep sperm 11 on the correct path toward the egg. However, it is not known how the beating patterns of sperm 12 may influence these navigational strategies. In this study, we investigate the effect of flagellar 13 beating pattern on navigation of sperm cells both theoretically and experimentally using a two-14 step approach. We first isolate bovine sperm based on their rheotactic behavior in a zone with 15 quiescent medium using a microfluidic system. This step ensures that the swimmers are able to 16 navigate upstream and have motilities higher than a selected value, even though they feature 17 various flagellar beating patterns. We then explore the flagellar beating pattern of these isolated 18 sperm and their subsequent influence on boundary-dependent navigation. Our findings indicate 19 that rheotaxis enables sperm to navigate upstream even in the presence of circular motion in their 20 motility, whereas boundary-dependent navigation is more sensitive to the circular motion and 21 selects for progressive motility. This finding may explain the clinical importance of progressive 23 the sperm cells throughout the process of insemination. 24 Keywords: Mammalian sperm | Navigation | Rheotaxis | Boundary-dependent navigation | 25 Progressive motility 26 Significance 27Finding the egg and moving toward it while traversing the complex structure of the female 28 reproductive tract is necessary for mammalian sperm. Previous studies have shown how sperm use 29 navigational steering mechanisms that are based on swimming upstream (i.e. rheotaxis) and along 30 the boundaries of the female reproductive tract. We demonstrate that the performance of theses 31 navigational mechanisms is associated with the primary characteristics of sperm motility. In fact, 32 sperm rheotaxis is more sensitive to the motility and thus average velocity of sperm while 33 navigation via rigid boundaries is more sensitive to the flagellar beating pattern and selects for 34 symmetric beating. Our results can be expanded to other autonomous microswimmers and their 35 subsequent navigation mechanisms. 36 37 38 39 40 41 42 43 48which vary among different species. For instance, marine plants and animals (10, 11) release their 49 gametes into the sea, where chemotactic behavior is observed (4,(11)(12)(13). Strikingly, the role of 50 this chemical communication observed in marine invertebrate sperm (which is reminiscent of 51 bacterial chemotaxis (14)) is uncertain in the navigation of mammalian sperm (13,(15)(16)(17)(18)(19). In 52 contrast, in vitro/vivo evidence suggests that the navigation of mammalian sperm within the female 53 reproductive tract depends more on fluid mechanical c...

show abstract

Strictures of a microchannel impose fierce competition to select for highly motile sperm

Abstract: Motility-based competition dynamics at microfluidic strictures suggests a sperm-selection mechanism in the reproductive tract.

Cited by 67 publications

References 39 publications

Differential sperm motility mediates the sex ratio drive shaping mouse sex chromosome evolution

Differential sperm motility mediates the sex ratio drive shaping mouse sex chromosome evolution

Progressive Sperm Separation Using Parallelized, High-Throughput, Microchamber-based Microfluidics

Effect of flagellar beating pattern on sperm rheotaxis and boundary-dependent navigation

Contact Info

Product

Resources

About