Project description:We proposed that DNA recombination/repair processes play a role in memory formation. Here, we used microarray analysis of rat amygdala genes to identify possible DNA recombination/repair factors involved in memory consolidation of conditioned taste aversion (CTA). Among the genes that showed statistically significant differential expression, we identified fen-1, encoding a flap-structure specific DNA endonuclease. Amygdalar fen-1 mRNA induction was associated to the illness component of CTA, since it could be observed by the pairing of a flavor and gastrointestinal illness, by the illness itself, but not by the presentation of the flavor alone. No CTA related induction of fen-1 expression was observed in the insular cortex. Importantly, functional validation studies demonstrated that amygdalar suppression of fen-1 expression impaired memory consolidation of CTA. Overall, our studies helped identify a new DNA recombination/repair candidate factor involved in memory formation of aversive experiences.
Project description:Bruton’s tyrosine kinase (BTK) is an intracellular signaling enzyme that regulates B cell and myeloid cell functions. Due to its involvement in both innate and adaptive immune compartments, inhibitors of BTK have emerged as a therapeutic option in autoimmune disorders such as multiple sclerosis (MS). Brain penetrant small molecule BTK inhibitors may also help to address compartmentalized neuroinflammation which is proposed to underlie MS disease progression. BTK is expressed by microglia, the resident innate immune cells of the brain, however the precise roles of microglial BTK and the impact of BTK inhibitors on microglial functions is still being elucidated. Much research to date has also focused on the effects of BTK inhibitors using rodent disease models. Here we characterize the pharmacological and functional properties of fenebrutinib (FEN), a potent, highly selective, noncovalent, reversible BTK inhibitor, in human microglia and complex human brain cell systems including brain organoids. We find that FEN blocks the effects of microglial FcγR activation including cytokine and chemokine release, microglial clustering and neurite damage in diverse human brain cell systems. Gene expression analyses identified pathways linked to inflammation, matrix metalloproteinase production and cholesterol metabolism that were modulated by FEN treatment. In contrast, FEN had no significant impact on human microglial pathways linked to TLR4 or NLRP3 signaling nor myelin phagocytosis. Our study increases the understanding of BTK functions in human microglial signaling relevant to MS pathogenesis and suggests that FEN could attenuate detrimental microglial activity associated with FcγR activation in MS patients.
Project description:We proposed that DNA recombination/repair processes play a role in memory formation. Here, we used microarray analysis of rat amygdala genes to identify possible DNA recombination/repair factors involved in memory consolidation of conditioned taste aversion (CTA). Among the genes that showed statistically significant differential expression, we identified fen-1, encoding a flap-structure specific DNA endonuclease. Amygdalar fen-1 mRNA induction was associated to the illness component of CTA, since it could be observed by the pairing of a flavor and gastrointestinal illness, by the illness itself, but not by the presentation of the flavor alone. No CTA related induction of fen-1 expression was observed in the insular cortex. Importantly, functional validation studies demonstrated that amygdalar suppression of fen-1 expression impaired memory consolidation of CTA. Overall, our studies helped identify a new DNA recombination/repair candidate factor involved in memory formation of aversive experiences. Two comparisons were established between the cRNA samples: CTA versus Flavor-only and CTA versus Toxin-only. For each comparison, the microarray experiment was repeated four times using new biological samples, each consisting of a sample pool from 3 animals. Two of the four biological replicates were performed as dye-swaps in order to correct for dye bias effects.
Project description:Analyses of new genomic, transcriptomic or proteomic data commonly result in trashing many unidentified data escaping the ‘canonical’ DNA-RNA-protein scheme. Testing systematic exchanges of nucleotides over long stretches produces inversed RNA pieces (here named “swinger” RNA) differing from their template DNA. These may explain some trashed data. Here analyses of genomic, transcriptomic and proteomic data of the pathogenic Tropheryma whipplei according to canonical genomic, transcriptomic and translational 'rules' resulted in trashing 58.9% of DNA, 37.7% RNA and about 85% of mass spectra (corresponding to peptides). In the trash, we found numerous DNA/RNA fragments compatible with “swinger” polymerization. Genomic sequences covered by «swinger» DNA and RNA are 3X more frequent than expected by chance and explained 12.4 and 20.8% of the rejected DNA and RNA sequences, respectively. As for peptides, several match with “swinger” RNAs, including some chimera, translated from both regular, and «swinger» transcripts, notably for ribosomal RNAs. Congruence of DNA, RNA and peptides resulting from the same swinging process suggest that systematic nucleotide exchanges increase coding potential, and may add to evolutionary diversification of bacterial populations.