Adenylate kinase phosphate energy shuttle underlies energetic communication in flagellar axonemes

The complexities of energy transfer mechanisms in the flagella of mammalian sperm flagella have been intensively investigated and demonstrate significant diversity across species.Enzymatic shuttles,particularly adenylate kinase(AK)and creatine kinase(CK),are pivotal in the efficient transfer of intracellular ATP,showing distinct tissue-and species-specificity.Here,the expression profiles of AK and CK were investigated in mice and found to fall into four subgroups,of which Subgroup III AKs were observed to be unique to the male reproductive system and conserved across chordates.Both AK8 and AK9 were found to be indispensable to male reproduction after analysis of an infertile male cohort.Knockout mouse models showed that AK8 and AK9 were central to promoting sperm motility.Immunoprecipitation combined with mass spectrometry revealed that AK8 and AK9 interact with the radial spoke(RS)of the axoneme.Examination of various human and mouse sperm samples with substructural damage,including the presence of multiple RS subunits,showed that the head of radial spoke 3 acts as an adapter for AK9 in the flagellar axoneme.Using an ATP probe together with metabolomic analysis,it was found that AK8 and AK9 cooperatively regulated ATP transfer in the axoneme,and were concentrated at sites associated with energy consumption in the flagellum.These findings indicate a novel function for RS beyond its structural role,namely,the regulation of ATP transfer.In conclusion,the results expand the functional spectrum of AK proteins and suggest a fresh model regarding ATP transfer within mammalian flagella.

A homozygous frameshift mutation in ADAD2 causes male infertility with spermatogenic impairments

Male infertility is a complex reproductive disorder that impedes a huge number of couples from having children naturally in the world(Agarwal et al.,2021).As an important pathogenic factor of male infertility,spermatogenic impairments are mainly characterized by impaired male gamete production,reduced sperm quality,or function(Tournaye et al.,2017).Spermatogenesis is a delicate and complex biological process that requires the collaboration of a large number of proteins performing different biological functions(Liu et al.,2021).

Nanomechanical vibration profiling of oocytes

The beginning of a mammalian life commences with a fertilized oocyte.The study of oocytes is certainly one of the most intriguing scientific questions of our time.Herein,we studied oocytes from a mechanical perspective and characterized the typical life activities of oocytes by nanomechanical vibrations.During the development of oocytes from the germinal vesicle(GV)stage to the zygotes,the GV stage oocytes induced a significant nanomechanical vibration,compared with the oocytes in meiosis I(MI)and meiosis II(MII)stages and zygotes.We analyzed the characteristics of mechanical vibrations of oocytes,including the amplitude as well as the frequency.It showed that the amplitude and frequency of nanomechanical vibrations induced by oocytes were caused by the cytoskeleton(microfilaments)and the distribution of metabolic characteristics(mitochondria)within oocytes.This work provides a new perspective for clinical quality assessment and basic research of oocytes,and can open new doors for development of life science.

Quantifying 3D cell-matrix interactions during mitosis and the effect of anticancer drugs on the interactions

The mechanical force between cells and the extracellular microenvironment is crucial to many physiological processes such as cancer metastasis and stem cell differentiation. Mitosis plays an essential role in all these processes and thus an in-depth understanding of forces during mitosis gains insight into disease diagnosis and disease treatment. Here, we develop a traction force microscope method based on monolayer fluorescent beads for measuring the weak traction force (tens of Pa) of mitotic cells in three dimensions. We quantify traction forces of human ovarian granulosa (KGN) cells exerted on the extracellular matrix throughout the entire cell cycle in three dimensions. Our measurements reveal how forces vary during the cell cycle, especially during cell division. Furthermore, we study the effect of paclitaxel (PTX) and nocodazole (NDZ) on mitotic KGN cells through the measurement of traction forces. Our results show that mitotic cells with high concentrations of PTX exert a larger force than those with high concentrations of NDZ, which proved to be caused by changes in the structure and number of microtubules. These findings reveal the key functions of microtubule in generating traction forces during cell mitosis and explain how dividing cells regulate themselves in response to anti-mitosis drugs. This work provides a powerful tool for investigating cell-matrix interactions during mitosis and may offer a potential way to new therapies for cancer.

A microfluidic approach for synchronous and nondestructive study of the permeability of multiple oocytes

Investigation of oocyte membrane permeability plays a crucial role in fertility preservation,reproductive medicine,and reproductive pharmacology.However,the commonly used methods have disadvantages such as high time consumption,low efficiency,and cumbersome data processing.In addition,the developmental potential of oocytes after measurement has not been fully validated in previous studies.Moreover,oocytes can only maintain their best status in vitro within a very limited time.To address these limitations,we developed a novel multichannel microfluidic chip with newly designed micropillars that provide feasible and repeatable oocyte capture.The osmotic responses of three oocytes at different or the same cryoprotectant(CPA)concentrations were measured simultaneously,which greatly improved the measurement efficiency.Importantly,the CPA concentration dependence of mouse oocyte membrane permeability was found.Moreover,a neural network algorithm was employed to improve the efficiency and accuracy of data processing.Furthermore,analysis of fertilization and embryo transfer after perfusion indicated that the microfluidic approach does not damage the developmental potential of oocytes.In brief,we report a new method based on a multichannel microfluidic chip that enables synchronous and nondestructive measurement of the permeability of multiple oocytes.

Novel compound heterozygous variants in dynein axonemal heavy chain 17 cause asthenoteratospermia with sperm flagellar defects

The axoneme of the human sperm has a very similar ultrastructure to motile cilia,the"9+2"structure,comprising nine peripheral double microtubules plus two central pairs(Nicastro et al.,2006;Ishikawa,2017).A proteomics analysis identified more than700 proteins exclusively in the sperm tail,and abnormal expression of related genes can cause male infertility with multiple morphological abnormalities of flagella(MMAF),including absent,coiled,short,and irregular-caliber flagella(Baker et al.,2013;Coutton et al.,2015).

Maternal heterozygous mutation in CHEK1 leads to mitotic arrest in human zygotes

Dear Editor,The first mitotic division in zygotes is crucial for the beginning of the life cycle for the human.After fertilization,zygotes reactivate cell cycle,both paternal and maternal genomes replicate and reprogram to become totipotent.In the meantime,the male and female pronucleus move to the center of the zygote and merge.Then zygotes enter the metaphase,and sister chromatids separate into two daughter cells(Eckersley-Maslin et al.,2018;Reichmann et al.,2018).This is a sensitive time window and many perturbances may cause the first mitosis to fail.