Witke, W. | Search bioRxiv

bioRxiv2024

Deficiency of actin depolymerizing factors ADF/Cfl1 in microglia decreases motility and impairs memory

Microglia are highly motile cells that play a crucial role in the central nervous system in health and disease. Here we show that actin depolymerizing factors ADF and Cofilin1 (Cfl1) are key factors of microglia integrity and function. We found a profound morphological phenotype in absence of ADF and Cfl1 in microglia. In vivo two-photon imaging of microglia with ADF/Cfl1-KO revealed reduced microglial fine processes motility and impaired microglia migration towards a laser-induced lesion. We found increased accumulation of stabilized F-actin and altered microtubule dynamics in ADF/Cfl1-KO microglia, indicating that ADF/Cfl1 are necessary for microglial cytoskeleton dynamics. Interestingly, microglial ADF/Cfl1-deficiency decreased learning and memory, suggesting that impaired microglial cytoskeleton dynamics affect neuronal functions relevant for cognition. Our results reveal a fundamental role of ADF/Cfl1 in microglia function and underscore the importance of these innate immune cells for higher cognitive functions.

neuroscience↗

bioRxiv2022

Actl7b-deficiency leads to mislocalization of LC8 type dynein light chains and disruption of murine spermatogenesis

Actin-related proteins (Arp) are classified according to their similarity to actin and are involved in diverse cellular processes. ACTL7B is a testis-specific Arp and highly conserved in rodents and primates. ACTL7B is specifically expressed in round and elongating spermatids during spermiogenesis. Here, we have generated an Actl7b-null allele in mice to unravel the role of ACTL7B in sperm formation. Male mice homozygous for the Actl7b-null allele (Actl7b-/-) were infertile, while heterozygous males (Actl7b+/-) were fertile. Severe spermatid defects such as detached acrosomes, disrupted membranes and failed elongation of the axoneme start to appear at spermiogenesis step 9 in Actl7b-/- mice, finally resulting in spermatogenic arrest. Abnormal spermatids, were degraded. Co-immunoprecipitation experiments identified interaction between ACTL7B and the LC8 dynein light chains DYNLL1 and DYNLL2, which are first detected in step 9 spermatids and mislocalized when ACTL7B is absent. Our data unequivocally establishes that mutations in ACTL7B are directly related to male infertility, pressing for additional research in men. Summary statementIn this study, Actl7b-deficient mice were generated. Loss of Actl7b leads to spermatogenic arrest in mice. ACTL7B interacts in with DYNLL1/DYNLL2 and seems to function in spermatid cytoskeleton.

developmental biology↗