Biology subjects

Hartl, D.

Publications and source records attributed to Hartl, D..

3 recordsLinked to original sources

bioRxiv2018

Targeting neuronal and glial cell types with synthetic promoter AAVs in mice, non-human primates, and humans

Targeting genes to specific neuronal or glial cell types is valuable both for understanding and for repairing brain circuits. Adeno-associated viral vectors (AAVs) are frequently used for gene delivery, but targeting expression to specific cell types is a challenge. We created a library of 230 AAVs, each with a different synthetic promoter designed using four independent strategies. We show that ~11% of these AAVs specifically target expression to neuronal and glial cell types in the mouse retina, mouse brain, non-human primate retina in vivo, and in the human retina in vitro. We demonstrate applications for recording, stimulation, and molecular characterization, as well as the intersectional and combinatorial labeling of cell types. These resources and approaches allow economic, fast, and efficient cell-type targeting in a variety of species, both for fundamental science and for gene therapy.

neuroscience↗

bioRxiv2018

Complexes of RNA and the antimicrobial peptide, LL37, trigger TLR-mediated cytokine release from psoriasis neutrophils

Psoriasis is an inflammatory autoimmune disease characterized by skin lesions showing strong neutrophil (PMN) infiltration and high levels of the antimicrobial peptide, LL37, but the role of PMNs in this context remains unclear. We here show that primary human PMNs, especially PMNs from psoriasis patients, not only respond via TLR8 to human and bacterial RNA in complexed with LL37 by cytokine-, chemokine- and neutrophil extracellular trap (NET)-release; they also actively release additional RNA and LL37 in response to stimulation by the same complex and both RNA and LL37 were found to be highly abundant in psoriatic skin. Moreover, RNA-LL37-induced NETs propagated PMN activation and could thus fuel a PMN-mediated and self-sustaining inflammatory loop that may represent an unexpected early initiator or amplifying event in psoriasis. Given that TLR inhibitory oligodeoxynucleotides prevented the cytokine production and NETosis of PMNs by RNA-LL37 complexes in vitro, our study also highlights TLR blockade as a potential therapeutic intervention strategy in psoriasis. SummaryHuman and bacterial RNA in complex with LL37 activates neutrophils via TLR8 to release cytokines, chemokines and neutrophil extracellular traps (NETs). NETs and neutrophil-rich areas in psoriatic skin contain RNA and LL37, suggesting RNA-LL37 may fuel a PMN-mediated and self-sustaining inflammatory cycle in psoriasis.

immunology↗

bioRxiv2018

The fungal ligand chitin directly binds and signals inflammation dependent on oligomer size and TLR2

Chitin is a highly abundant polysaccharide and linked to fungal infection and asthma. Unfortunately, its polymeric structure has hampered the identification of immune receptors directly binding chitin and signaling immune activation and inflammation, because purity, molecular structure and molarity are not well definable for a polymer typically extracted from biomass. Therefore, by using defined chitin (N-acetyl-glucosamine) oligomers, we identified six subunit long chitin chains as the smallest immunologically active motif and the innate immune receptor Toll-like receptor (TLR) 2 as the primary fungal chitin receptor on human and murine immune cells. Chitin oligomers directly bound TLR2 with nanomolar affinity and showed both overlapping and distinct signaling outcomes compared to known mycobacterial TLR2 ligands. Conversely, chitin oligomers shorter than 6 subunits were inactive or showed antagonistic effects on chitin/TLR2-mediated signaling, hinting to a size-dependent sensing/activation system unexpectedly conserved in plants and humans. Since blocking the chitin-TLR2 interaction effectively prevented chitin-mediated inflammation in vitro and in vivo, our study highlights the chitin TLR2 interaction as a potential target for developing novel therapies in chitin-related pathologies and fungal disease.

immunology↗