Biology subjects

Reineking, W.

Publications and source records attributed to Reineking, W..

4 recordsLinked to original sources

bioRxiv2025

Synergistic interference with SARS-CoV-2 replication by Molnupiravir-derived N4 hydroxycytidine and inhibitors of CTP synthetase

N4-hydroxycytidine (NHC), the active metabolite of Molnupiravir, is incorporated into nascent RNA of SARS-CoV-2 and interferes with subsequent virus replication. We have previously described synergy between NHC and inhibitors of dehydroorotate dehydrogenase (DHODH), an enzyme required for pyrimidine synthesis. Upon DHODH inhibition, the lack of endogenous pyrimidines conceivably enhances NHC incorporation. However, the question remains whether preventing the synthesis of just one pyrimidine base, cytidine, might as well augment the antiviral efficacy of NHC. We tested this by inhibiting CTP synthetases (CTPSs), the cellular enzymes that directly catalyze the synthesis of a cytidine nucleotide. We observed that inhibitors of CTP synthetase (CTPSis), namely cyclopentenyl cytosine (CPEC) as well as STP938 and STP720, display a strong synergy with NHC for diminishing SARS-CoV-2 replication in cell culture, as shown earlier for DHODH inhibitors. NHC and CTPSis in combination prevented the cytopathic effect of SARS-CoV-2 and strongly reduced the release of viral RNA and infectious particles, as well as the synthesis of viral proteins. This combination was also active against an Omicron variant of SARS-CoV-2. Addition of cytidine, but not uridine, rescued virus growth under these conditions. Of note, treating SARS-CoV-2-infected hamsters with the CTPS1 inhibitor STP938 strongly diminished COVID pathology. We propose that CTPS inhibition has the potential to increase the efficacy of antiviral cytidine analogues and to treat coronavirus infections. HIGHLIGHTSO_LIThe efficacy of NHC against SARS-CoV-2 replication in cell culture models is intensified by several orders of magnitude through targeting cellular CTP-Synthetase. C_LIO_LIThe drug combination still displays its effect against SARS-CoV-2 replication in the presence of uridine, suggesting that serum uridine cannot counteract its efficacy. C_LIO_LICTPS inhibition diminishes COVID-19-like pathology in an established animal model. C_LI

microbiology↗

bioRxiv2025

Color-neutral and reversible tissue transparency enables longitudinal deep-tissue imaging in live mice

Light scattering in biological tissue presents a significant challenge for deep in vivo imaging. Our previous work demonstrated the ability to achieve optical transparency in live mice using intensely absorbing dye molecules, which created transparency in the red spectrum while blocking shorter-wavelength photons. In this paper, we extend this capability to achieve optical transparency across the entire visible spectrum by employing molecules with strong absorption in the ultraviolet spectrum and sharp absorption edges that rapidly decline upon entering the visible spectrum. This new color-neutral and reversible tissue transparency method enables optical transparency for imaging commonly used fluorophores in the green and yellow spectra. Notably, this approach facilitates tissue transparency for structural and functional imaging of the live mouse brain labeled with yellow fluorescent protein and GCaMP through the scalp and skull. We show that this method enables longitudinal imaging of the same brain regions in awake mice over multiple days during development. Histological analyses of the skin and systemic toxicology studies indicate minimal acute or chronic damage to the skin or body using this approach. This color-neutral and reversible tissue transparency technique opens new opportunities for noninvasive deep-tissue optical imaging, enabling long-term visualization of cellular structures and dynamic activity with high spatiotemporal resolution and chronic tracking capabilities. Significance StatementTissue scattering represents a major barrier to deep tissue imaging in vivo. We recently showed that tissue can be rendered transparent in the red spectrum using intensely absorbing dye molecules. Here, we introduce a new, color-neutral and reversible tissue transparency approach. We demonstrate longitudinal structural and functional imaging in the deep tissue of awake mice.

bioengineering↗

bioRxiv2025

Ptpn14 Knockout Mice Reveal Critical Female-Specific Roles for the Hippo Pathway

The Hippo pathway regulates many physiological processes, including development, tumor suppression, and wound healing. One understudied Hippo pathway component is PTPN14, an evolutionarily conserved tyrosine-phosphatase that inhibits YAP/TAZ. While an established tumor suppressor, PTPN14s role in tissue homeostasis has remained unclear. We thus generated Ptpn14-deficient mice and found that only [~]60% of Ptpn14-/- mice survived postnatally, highlighting the importance of PTPN14 for viability, while also enabling the discovery of PTPN14 physiological functions. Ptpn14-/-mice developed debilitating corneal lesions and the uterus defect, hydrometra, as well as heart and kidney abnormalities. Ptpn14-deficiency precipitated an impaired injury response in the cornea and dysregulated YAP signaling in the uterus. Notably, these phenotypes were female-specific, revealing sexually-dimorphic Hippo pathway function through PTPN14. Finally, analysis of human PTPN14 variants suggested that PTPN14s essential roles are conserved in humans, underscoring the importance of our insights for designing therapies to improve womens health.

developmental biology↗

bioRxiv2024

Inhibitors of dihydroorotate dehydrogenase synergize with the broad antiviral activity of 4'-fluorouridine

RNA viruses present a constant threat to human health, often with limited options for vaccination or therapy. Notable examples include influenza viruses and coronaviruses, which have pandemic potential. Filo- and henipaviruses cause more limited outbreaks, but with high case fatality rates. All RNA viruses rely on the activity of a virus-encoded RNA-dependent RNA polymerase (RdRp). An antiviral nucleoside analogue, 4'-Fluorouridine (4'-FlU), targets RdRp and diminishes the replication of several RNA viruses, including influenza A virus and SARS-CoV-2, through incorporation into nascent viral RNA and delayed chain termination. However, the effective concentration of 4'-FlU varied among different viruses, raising the need to fortify its efficacy. Here we show that inhibitors of dihydroorotate dehydrogenase (DHODH), an enzyme essential for pyrimidine biosynthesis, can synergistically enhance the antiviral effect of 4'-FlU against influenza A viruses, SARS-CoV-2, henipaviruses, and Ebola virus. Even 4'-FlU-resistant mutant influenza A virus was re-sensitized towards 4'-FlU by DHODH inhibition. The addition of uridine rescued influenza A virus replication, strongly suggesting uridine depletion as a mechanism of this synergy. 4'-FlU was also highly effective against SARS-CoV-2 in a hamster model of COVID. We propose that the impairment of endogenous uridine synthesis by DHODH inhibition enhances the incorporation of 4'-FlU into viral RNAs. This strategy may be broadly applicable to enhance the efficacy of pyrimidine nucleoside analogues for antiviral therapy. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=104 SRC="FIGDIR/small/616778v1_ufig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@398504org.highwire.dtl.DTLVardef@4befaeorg.highwire.dtl.DTLVardef@1648bbcorg.highwire.dtl.DTLVardef@12169e_HPS_FORMAT_FIGEXP M_FIG C_FIG HIGHLIGHTSO_LIStrong synergy of DHODH inhibitors with 4'-FlU C_LIO_LIActivity of the combination against previously resistant influenza virus C_LIO_LIBroadly active combination against a diverse set of RNA viruses C_LIO_LISuccessful targets include highly pathogenic Ebola and Nipah viruses C_LI

microbiology↗