bioRxiv Science⌕ Search

Biology subjects

Hintze, J.

Publications and source records attributed to Hintze, J..

3 recordsLinked to original sources

Mind the translational gap: human microglia differ from mouse microglia in their regulation of Kv and Kir2.1 channels

K+ channels are important for controlling membrane potential and regulating functional properties of microglia. Whereas the inward-rectifying K+ (Kir) channel 2.1 modulates proliferation, voltage-gated K+ channels (Kv) are linked to inflammatory response in mouse microglia (mMG). These channels serve as possible drug targets but little is known regarding their activity in human microglia. We used patch-clamp recording to study membrane currents of primary human microglia (hMG) and human induced pluripotent stem cell-derived microglia-like cells (hiPSC-MGL) and compared them with mMG. Unlike mMG, hMG and hiPSC-MGL exhibited Kir2.1 currents only after LPS+IFN-{gamma} stimulation. Interestingly, Kv currents were not observed in hMG or hiPSC-MGL under any condition. While mMG had a progressively ameboid morphology after stimulation, hMG showed few morphological changes and hiPSC-MGL increased ramification. Overall, the activity of Kir2.1 and Kv channels in hMG and hiPSC-MGL differs fundamentally from mMG. Our findings highlight differences between species and underscore the need for translational approaches.

neuroscience↗

The Ligand Preference of LRP1 is Regulated by O-glycans

Low-density lipoprotein receptor (LDLR) and LDLR-related proteins (LRPs) are endocytic receptors serving as essential physiological regulators of multiple processes including cholesterol clearance, protein reabsorption and neuronal protein trafficking. We originally discovered O-glycans in linkers of the ligand-binding domains of LDLR/LRP receptors and showed that these play critical roles for uptake of LDL by LDLR and albumin by LRP2. Remarkably, these linker O-glycans are introduced exclusively by GALNT11, one out of 20 polypeptide GalNAc-transferase isoenzymes. Here, we investigate the role of linker O-glycans on the large ([~]600 kDa) and widely expressed multiligand LRP1 receptor implicated in diseases including neuropathies. In genetically engineered cell models we activated endogenous full-coding LRP1 with and without O-glycans and demonstrate that while the uptake of certain ligands, such as RAP and ApoE, was unaffected by O-glycans, the uptake of the neurotoxic molecules tau and amyloid beta was altered and in opposite directions. This demonstrates that O-glycans in ligand-binding domains can differentially modulate ligand affinity and specificity of LRP1. Our findings highlight an overlooked regulatory mechanism of endocytic receptors and identify the ligand repertoire of LRP1 as being influenced by O-glycans, with potential implications for neurodegenerative disease.

molecular biology↗

Conservation and discreteness of the atromentin gene cluster in fungi

The atromentin synthetase gene cluster is responsible for catalyzing the precursor pigment atromentin, which is further catalyzed into hundreds of different pigments that span different taxa in the Basidiomycota and is a distinguished feature of Boletales. Previous work identified co-transcription of the two essential clustered atromentin genes (the atromentin synthetase (NPS) and the aminotransferase) by inducible pigment conditions and also conserved genetic elements in the promoter regions (motifs). For this work, we found that the NPS and its promoter motif appeared to follow the same evolutionary path as the mushrooms. The NPS appears to predate Boletales and originate in Agaricomycetes, and with convergent/parallel evolution that allowed ascomycetes to produce atromentin. Additionally, a consensus of the intron-exon gene structure for basidiomycetous, atromentin-catalyzing NPSs was identified whereby a significant deviation occurred in the paraphyletic group, Paxillaceae. This gene structure was not present in NPSs in Aspergilli. Lastly, we found a putative TATA box adjacent to the palindromic motif of NPS, indicating (co-)transcriptional control by a TATA(-like) binding transcription factor. Combined with previous decades worth of research, our results support that not only can atromentin derivatives be used for chemo-taxonomy, but also atromentins genetic basis. Future work using the putative promoter motif will provide new insight into which (co-)transcription factor may be responsible for the transcriptional control of atromentin synthetases.

bioinformatics↗