Biology subjects

Goretzko, J.

Publications and source records attributed to Goretzko, J..

3 recordsLinked to original sources

bioRxiv2021

Leukocyte adhesion is governed by endolysosomal two pore channel 2 (TPC2)

In response to pro-inflammatory challenges including pathogenic attack and tissue damage, the endothelial cell surface is rearranged to present leukocyte-engaging cell surface receptors. The initial contact needed for leukocyte tethering and rolling is mediated via adhesion demand-driven exocytosis of Weibel-Palade bodies (WPB) that contain the leukocyte receptor P-selectin together with the stabilizing co-factor CD63. We found that diminished expression of the endolysosomal non-selective cation channel TPC2 or inhibition of TPC2-mediated Ca2+-release via trans-Ned 19 led to reduced endolysosomal Ca2+ efflux, and blocked transfer of CD63 from late endosomes/lysosomes (LEL) to WPB, and a concomitant loss of P-selectin on the endothelial cell surface. Accordingly, P-selectin-mediated leukocyte recruitment to trans-Ned 19-treated HUVEC under flow was significantly reduced without disturbing VWF exocytosis. Our findings establish the endolysosome-related TPC2 Ca2+ channel as a key element in the maintenance of proper endothelial functions and a potential pharmacological target in the control of inflammatory leukocyte recruitment.

immunology↗

bioRxiv2020

Conserved cholesterol-related activities of Dispatched drive Sonic hedgehog shedding from the cell membrane

The Sonic hedgehog (Shh) pathway controls embryonic development and tissue homeostasis after birth. Long-lasting questions about this pathway are how dual-lipidated, firmly plasma membrane-associated Shh ligand is released from producing cells to signal to distant target cells, and how the resistance-nodulation-division transporter Dispatched (Disp) regulates this process. Here we show that Disp inactivation in Shh expressing cells specifically impairs proteolytic Shh release from its lipidated terminal peptides, a process called ectodomain shedding. Shh shedding from Disp-deficient cells was restored by pharmacological membrane cholesterol extraction and by overexpressed transgenic Disp or structurally related Patched (Ptc, a putative cholesterol transporter). These data suggest that Disp regulates physiological Shh function via controlled cell surface shedding and that molecular mechanisms shared by Disp and Ptc exercise such sheddase control.

cell biology↗

bioRxiv2020

Targeting the endolysosomal host-SARS-CoV-2 interface by the clinically licensed antidepressant fluoxetine

The Corona Virus Disease 2019 (COVID-19) pandemic caused by the Severe Acute Respiratory Syndrome Related Coronavirus 2 (SARS-CoV-2) is a global health emergency. As only very limited therapeutic options are clinically available, there is an urgent need for the rapid development of safe, effective, and globally available pharmaceuticals that inhibit SARS-CoV-2 entry and ameliorate COVID-19. In this study, we explored the use of small compounds acting on the homeostasis of the endolysosomal host-pathogen interface, to fight SARS-CoV-2 infection. We find that fluoxetine, a widely used antidepressant and a functional inhibitor of acid sphingomyelinase (FIASMA), efficiently inhibited the entry and propagation of SARS-CoV-2 in the cell culture model without cytotoxic effects and also exerted potent antiviral activity against two currently circulating influenza A virus subtypes, an effect which was also observed upon treatment with the FIASMAs amiodarone and imipramine. Mechanistically, fluoxetine induced both impaired endolysosomal acidification and the accumulation of cholesterol within the endosomes. As the FIASMA group consists of a large number of small compounds that are well-tolerated and widely used for a broad range of clinical applications, exploring these licensed pharmaceuticals may offer a variety of promising antivirals for host-directed therapy to counteract enveloped viruses, including SARS-CoV-2 and COVID 19.

microbiology↗