Claus, D. | bioRxiv Science

bioRxiv2026

Semaphorin 3G (SEMA3G) is a highly selective marker of cerebral amyloid angiopathy

Biomarkers of cerebral amyloid angiopathy (CAA) are critically needed. We recently identified semaphorin 3G (SEMA3G) as a novel protein selectively enriched in CAA. Here, we aimed to determine if SEMA3G was a selective marker of CAA in a large cohort of human brain tissue spanning multiple neurodegenerative diseases and three brain regions, and to determine if SEMA3G directly interacts with amyloid beta (A{beta}). Multiplexed immunofluorescence showed that SEMA3G significantly accumulated only in CAA+ blood vessels in the brain in all cases. We also showed that SEMA3G preferentially associated with A{beta}40, A{beta}pS8 and A{beta}pE3, but not A{beta}42. Thioflavin T assays and transmission electron microscopy showed that SEMA3G directly interacted with A{beta} and slowed A{beta} aggregation in vitro, and that this effect was more pronounced for A{beta}40 than A{beta}42. Together our results demonstrate that SEMA3G is a highly specific marker of CAA in the brain.

neuroscience↗

bioRxiv2022

CRISPR/Cas9 mediated gene editing in non-model nematode Panagrolaimus sp. PS1159

The phylum Nematoda harbors a huge diversity of species in a broad range of ecosystems and habitats. Nematodes share a largely conserved Bauplan but major differences have been found in early developmental processes. The development of the nematode model organism Caenorhabditis elegans has been studied in great detail for decades. These efforts have provided the community with a large number of protocols and methods. Unfortunately, many of these tools are not easily applicable in non-Caenorhabditis nematodes. In recent years it has become clear that many crucial genes in the C. elegans developmental toolkit are absent in other nematode species. It is thus necessary to study the developmental program of other nematode species in detail to understand evolutionary conservation and novelty in the phylum. Panagrolaimus sp. PS1159 is a non-parasitic nematode exhibiting parthenogenetic reproduction and we are establishing the species to comparatively study evolution, biodiversity and alternative reproduction and survival strategies. Here, we demonstrate the first successful application of the CRISPR/Cas9 system for genome editing in Panagrolaimus sp. PS1159 and its closely related hermaphroditic species Propanagrolaimus sp. JU765 with both the non-homologous end joining and the homology-directed repair mechanism. Using microinjections and modifying published protocols from C. elegans and P. pacificus we induced mutations in the orthologue of unc-22, which resulted in a visible uncoordinated twitching phenotype. We also compared the HDR efficiency following the delivery of different repair templates. This work will expand the applicability for a wide range of non-model nematodes from across the tree and facilitate functional analysis into the evolution of parthenogenesis, changes in the developmental program of Nematoda, and cryptobiosis.

molecular biology↗