Propylene glycol inactivates respiratory viruses and prevents airborne transmission

Viruses are vulnerable as they transmit between hosts, and we aimed to exploit this critical window. We found that the ubiquitous, safe, inexpensive and biodegradable small molecule propylene glycol (PG) has robust virucidal activity. Propylene glycol rapidly inactivates a broad range of viruses including influenza A, SARS-CoV-2 and rotavirus and reduces disease burden in mice when administered intranasally at concentrations commonly found in nasal sprays. Most critically, vaporised PG efficiently abolishes influenza A virus and SARS-CoV-2 infectivity within airborne droplets, potently preventing infection at levels well below those tolerated by mammals. We present PG vapour as a first-in-class non-toxic airborne virucide that can prevent transmission of existing and emergent viral pathogens, with clear and immediate implications for public health

CRYPTOCHROMES confer robustness, not rhythmicity, to circadian timekeeping

Circadian rhythms are a pervasive property of mammalian cells, tissues and behaviour, ensuring physiological adaptation to solar time. Models of cellular timekeeping revolve around transcriptional feedback repression, whereby CLOCK and BMAL1 activate the expression of PERIOD (PER) and CRYPTOCHROME (CRY), which in turn repress CLOCK/BMAL1 activity. CRY proteins are therefore considered essential components of the cellular clock mechanism, supported by behavioural arrhythmicity of CRY‐deficient (CKO) mice under constant conditions. Challenging this interpretation, we find locomotor rhythms in adult CKO mice under specific environmental conditions and circadian rhythms in cellular PER2 levels when CRY is absent. CRY‐less oscillations are variable in their expression and have shorter periods than wild‐type controls. Importantly, we find classic circadian hallmarks such as temperature compensation and period determination by CK1δ/ε activity to be maintained. In the absence of CRY‐mediated feedback repression and rhythmic Per2 transcription, PER2 protein rhythms are sustained for several cycles, accompanied by circadian variation in protein stability. We suggest that, whereas circadian transcriptional feedback imparts robustness and functionality onto biological clocks, the core timekeeping mechanism is post‐translational

Role of Fas/FasL in regulation of inflammation in vaginal tissue during HSV-2 infection

To assess the role of Fas in lesion development during genital HSV-2 infection, we used a well-established HSV-2 murine model applied to MRL-Faslpr/J (Fas−/−) and C3-Faslgld/J (FasL−/−) C57BL6 mice. In vitro infection of murine keratinocytes and epithelial cells was used to clarify molecular details of HSV-2 infection. Despite upregulation of Fas and FasL, HSV-2-infected keratinocytes and epithelial cells showed a moderate level of apoptosis due to upregulated expression of the anti-apoptotic factors Bcl-2, Akt kinase and NF-κB. Inflammatory lesions within the HSV-2-infected epithelium of C57BL6 mice consisted of infected cells upregulating Fas, FasL and Bcl-2, uninfected cells upregulating Fas and neutrophils expressing both Fas and FasL. Apoptosis was detected in HSV-2-infected cells and to even higher extent in non-infected cells surrounding HSV-2 infection sites. HSV-2 infection of Fas- and FasL-deficient mice led to increased apoptosis and stronger recruitment of neutrophils within the infection sites. We conclude that the Fas pathway participates in regulation of inflammatory response in the vaginal epithelium at the initial stage of HSV-2 infection

Lysyl hydroxylase 3 localizes to epidermal basement membrane and Is reduced in patients with Recessive Dystrophic Epidermolysis Bullosa

Recessive dystrophic epidermolysis bullosa (RDEB) is caused by mutations in COL7A1 resulting in reduced or absent type VII collagen, aberrant anchoring fibril formation and subsequent dermal-epidermal fragility. Here, we identify a significant decrease in PLOD3 expression and its encoded protein, the collagen modifying enzyme lysyl hydroxylase 3 (LH3), in RDEB. We show abundant LH3 localising to the basement membrane in normal skin which is severely depleted in RDEB patient skin. We demonstrate expression is in-part regulated by endogenous type VII collagen and that, in agreement with previous studies, even small reductions in LH3 expression lead to significantly less secreted LH3 protein. Exogenous type VII collagen did not alter LH3 expression in cultured RDEB keratinocytes and we show that RDEB patients receiving bone marrow transplantation who demonstrate significant increase in type VII collagen do not show increased levels of LH3 at the basement membrane. Our data report a direct link between LH3 and endogenous type VII collagen expression concluding that reduction of LH3 at the basement membrane in patients with RDEB will likely have significant implications for disease progression and therapeutic intervention

Macromolecular condensation buffers intracellular water potential

Optimum protein function and biochemical activity critically depends on water availability because solvent thermodynamics drive protein folding and macromolecular interactions1. Reciprocally, macromolecules restrict the movement of 'structured' water molecules within their hydration layers, reducing the available 'free' bulk solvent and therefore the total thermodynamic potential energy of water, or water potential. Here, within concentrated macromolecular solutions such as the cytosol, we found that modest changes in temperature greatly affect the water potential, and are counteracted by opposing changes in osmotic strength. This duality of temperature and osmotic strength enables simple manipulations of solvent thermodynamics to prevent cell death after extreme cold or heat shock. Physiologically, cells must sustain their activity against fluctuating temperature, pressure and osmotic strength, which impact water availability within seconds. Yet, established mechanisms of water homeostasis act over much slower timescales2,3; we therefore postulated the existence of a rapid compensatory response. We find that this function is performed by water potential-driven changes in macromolecular assembly, particularly biomolecular condensation of intrinsically disordered proteins. The formation and dissolution of biomolecular condensates liberates and captures free water, respectively, quickly counteracting thermal or osmotic perturbations of water potential, which is consequently robustly buffered in the cytoplasm. Our results indicate that biomolecular condensation constitutes an intrinsic biophysical feedback response that rapidly compensates for intracellular osmotic and thermal fluctuations. We suggest that preserving water availability within the concentrated cytosol is an overlooked evolutionary driver of protein (dis)order and function

CRYPTOCHROMES confer robustness, not rhythmicity, to circadian timekeeping

Circadian rhythms are a pervasive property of mammalian cells, tissues and behaviour, ensuring physiological adaptation to solar time. Models of cellular timekeeping revolve around transcriptional feedback repression, whereby CLOCK and BMAL1 activate the expression of PERIOD (PER) and CRYPTOCHROME (CRY), which in turn repress CLOCK/BMAL1 activity. CRY proteins are therefore considered essential components of the cellular clock mechanism, supported by behavioural arrhythmicity of CRY-deficient (CKO) mice under constant conditions. Challenging this interpretation, we find locomotor rhythms in adult CKO mice under specific environmental conditions and circadian rhythms in cellular PER2 levels when CRY is absent. CRY-less oscillations are variable in their expression and have shorter periods than wild-type controls. Importantly, we find classic circadian hallmarks such as temperature compensation and period determination by CK1δ/ε activity to be maintained. In the absence of CRY-mediated feedback repression and rhythmic Per2 transcription, PER2 protein rhythms are sustained for several cycles, accompanied by circadian variation in protein stability. We suggest that, whereas circadian transcriptional feedback imparts robustness and functionality onto biological clocks, the core timekeeping mechanism is post-translational

Macromolecular condensation buffers intracellular water potential

Acknowledgements: The order of the second and corresponding authors is arbitrary and these authors can change the order of their respective names to suit their own interests. This work has been supported by the Medical Research Council, as part of United Kingdom Research and Innovation (MC_UP_1201/13 to E.D.; MC_UP_1201/4 to J.S.O. and MCMB MR/V028669/1 to J.E.C.), the Human Frontier Science Program (Career Development Award CDA00034/2017 to E.D.), a Versus Arthritis Senior Research Fellowship Award (20875 to Q.-J.M.) and an MRC project grant (MR/K019392/1 to Q.-J.M.), a Grifols ‘ALTA’ Alpha-1-Antitrypsin Laurell’s Training Award and an Alpha-1-Foundation (grant number 614939) to J.E.C., and by a Wellcome Trust Sir Henry Dale Fellowship (208790/Z/17/Z to R.S.E.). N.M.R. is supported by a Medical Research Council Clinician Scientist Fellowship (MR/S022023/1). L.K.K. and V.J.P.-H. are recipients of EMBO Postdoctoral fellowships (ALTF 876-2021 and ALTF 577-2018, respectively). K.E.M. is supported by the Wellcome Trust through a Sir Henry Wellcome Postdoctoral Fellowship (220480/Z/20/Z). P.M.M. and J.B. were supported by Volkswagen ‘Life’ grant number 96827 and the DFG Excellence Cluster Physics of Life. We thank H. Andreas for frog maintenance; C. Godlee and M. Kaksonen for the gift of unpublished S. cerevisiae yeast strains and initial discussion of yeast experiments about temperature; P. Tran for S. pombe yeast strains; L. Miller for help with yeast work; A. Bertolotti for the kind gift of SH-SY5Y cells; and C. Russo, F. Jülicher, M. Gonzalez-Gaitan, K. Kruse, L. Blanchoin, J. Löwe, R. Hegde, P. Farrell and P. Crosby for discussion and suggestions; the staff at the companies Cherry Biotech and Elvesys, in particular T. Guérinier, for their help in designing and assembling the custom microfluidics system required for this project; the members of the Electronics and Mechanical workshops of the LMB for key support; the staff at the LMB Mass Spectrometry facility for performing and analysing MS data; and A. Prasad and T. Stevens for sharing the scripts for protein disorder and kinase motif predictions, respectively. Cartoons were created using BioRender. For the purpose of open access, the MRC Laboratory of Molecular Biology has applied a CC BY public copyright licence to any author accepted manuscript version arising.Optimum protein function and biochemical activity critically depends on water availability because solvent thermodynamics drive protein folding and macromolecular interactions1. Reciprocally, macromolecules restrict the movement of ‘structured’ water molecules within their hydration layers, reducing the available ‘free’ bulk solvent and therefore the total thermodynamic potential energy of water, or water potential. Here, within concentrated macromolecular solutions such as the cytosol, we found that modest changes in temperature greatly affect the water potential, and are counteracted by opposing changes in osmotic strength. This duality of temperature and osmotic strength enables simple manipulations of solvent thermodynamics to prevent cell death after extreme cold or heat shock. Physiologically, cells must sustain their activity against fluctuating temperature, pressure and osmotic strength, which impact water availability within seconds. Yet, established mechanisms of water homeostasis act over much slower timescales2, 3; we therefore postulated the existence of a rapid compensatory response. We find that this function is performed by water potential-driven changes in macromolecular assembly, particularly biomolecular condensation of intrinsically disordered proteins. The formation and dissolution of biomolecular condensates liberates and captures free water, respectively, quickly counteracting thermal or osmotic perturbations of water potential, which is consequently robustly buffered in the cytoplasm. Our results indicate that biomolecular condensation constitutes an intrinsic biophysical feedback response that rapidly compensates for intracellular osmotic and thermal fluctuations. We suggest that preserving water availability within the concentrated cytosol is an overlooked evolutionary driver of protein (dis)order and function

Macromolecular condensation buffers intracellular water potential

Acknowledgements: The order of the second and corresponding authors is arbitrary and these authors can change the order of their respective names to suit their own interests. This work has been supported by the Medical Research Council, as part of United Kingdom Research and Innovation (MC_UP_1201/13 to E.D.; MC_UP_1201/4 to J.S.O. and MCMB MR/V028669/1 to J.E.C.), the Human Frontier Science Program (Career Development Award CDA00034/2017 to E.D.), a Versus Arthritis Senior Research Fellowship Award (20875 to Q.-J.M.) and an MRC project grant (MR/K019392/1 to Q.-J.M.), a Grifols ‘ALTA’ Alpha-1-Antitrypsin Laurell’s Training Award and an Alpha-1-Foundation (grant number 614939) to J.E.C., and by a Wellcome Trust Sir Henry Dale Fellowship (208790/Z/17/Z to R.S.E.). N.M.R. is supported by a Medical Research Council Clinician Scientist Fellowship (MR/S022023/1). L.K.K. and V.J.P.-H. are recipients of EMBO Postdoctoral fellowships (ALTF 876-2021 and ALTF 577-2018, respectively). K.E.M. is supported by the Wellcome Trust through a Sir Henry Wellcome Postdoctoral Fellowship (220480/Z/20/Z). P.M.M. and J.B. were supported by Volkswagen ‘Life’ grant number 96827 and the DFG Excellence Cluster Physics of Life. We thank H. Andreas for frog maintenance; C. Godlee and M. Kaksonen for the gift of unpublished S. cerevisiae yeast strains and initial discussion of yeast experiments about temperature; P. Tran for S. pombe yeast strains; L. Miller for help with yeast work; A. Bertolotti for the kind gift of SH-SY5Y cells; and C. Russo, F. Jülicher, M. Gonzalez-Gaitan, K. Kruse, L. Blanchoin, J. Löwe, R. Hegde, P. Farrell and P. Crosby for discussion and suggestions; the staff at the companies Cherry Biotech and Elvesys, in particular T. Guérinier, for their help in designing and assembling the custom microfluidics system required for this project; the members of the Electronics and Mechanical workshops of the LMB for key support; the staff at the LMB Mass Spectrometry facility for performing and analysing MS data; and A. Prasad and T. Stevens for sharing the scripts for protein disorder and kinase motif predictions, respectively. Cartoons were created using BioRender. For the purpose of open access, the MRC Laboratory of Molecular Biology has applied a CC BY public copyright licence to any author accepted manuscript version arising.Optimum protein function and biochemical activity critically depends on water availability because solvent thermodynamics drive protein folding and macromolecular interactions1. Reciprocally, macromolecules restrict the movement of ‘structured’ water molecules within their hydration layers, reducing the available ‘free’ bulk solvent and therefore the total thermodynamic potential energy of water, or water potential. Here, within concentrated macromolecular solutions such as the cytosol, we found that modest changes in temperature greatly affect the water potential, and are counteracted by opposing changes in osmotic strength. This duality of temperature and osmotic strength enables simple manipulations of solvent thermodynamics to prevent cell death after extreme cold or heat shock. Physiologically, cells must sustain their activity against fluctuating temperature, pressure and osmotic strength, which impact water availability within seconds. Yet, established mechanisms of water homeostasis act over much slower timescales2, 3; we therefore postulated the existence of a rapid compensatory response. We find that this function is performed by water potential-driven changes in macromolecular assembly, particularly biomolecular condensation of intrinsically disordered proteins. The formation and dissolution of biomolecular condensates liberates and captures free water, respectively, quickly counteracting thermal or osmotic perturbations of water potential, which is consequently robustly buffered in the cytoplasm. Our results indicate that biomolecular condensation constitutes an intrinsic biophysical feedback response that rapidly compensates for intracellular osmotic and thermal fluctuations. We suggest that preserving water availability within the concentrated cytosol is an overlooked evolutionary driver of protein (dis)order and function

Macromolecular condensation buffers intracellular water potential

Optimum protein function and biochemical activity critically depends on water availability because solvent thermodynamics drive protein folding and macromolecular interactions1. Reciprocally, macromolecules restrict the movement of 'structured' water molecules within their hydration layers, reducing the available 'free' bulk solvent and therefore the total thermodynamic potential energy of water, or water potential. Here, within concentrated macromolecular solutions such as the cytosol, we found that modest changes in temperature greatly affect the water potential, and are counteracted by opposing changes in osmotic strength. This duality of temperature and osmotic strength enables simple manipulations of solvent thermodynamics to prevent cell death after extreme cold or heat shock. Physiologically, cells must sustain their activity against fluctuating temperature, pressure and osmotic strength, which impact water availability within seconds. Yet, established mechanisms of water homeostasis act over much slower timescales2,3; we therefore postulated the existence of a rapid compensatory response. We find that this function is performed by water potential-driven changes in macromolecular assembly, particularly biomolecular condensation of intrinsically disordered proteins. The formation and dissolution of biomolecular condensates liberates and captures free water, respectively, quickly counteracting thermal or osmotic perturbations of water potential, which is consequently robustly buffered in the cytoplasm. Our results indicate that biomolecular condensation constitutes an intrinsic biophysical feedback response that rapidly compensates for intracellular osmotic and thermal fluctuations. We suggest that preserving water availability within the concentrated cytosol is an overlooked evolutionary driver of protein (dis)order and function.</p

Macromolecular condensation buffers intracellular water potential.

Acknowledgements: The order of the second and corresponding authors is arbitrary and these authors can change the order of their respective names to suit their own interests. This work has been supported by the Medical Research Council, as part of United Kingdom Research and Innovation (MC_UP_1201/13 to E.D.; MC_UP_1201/4 to J.S.O. and MCMB MR/V028669/1 to J.E.C.), the Human Frontier Science Program (Career Development Award CDA00034/2017 to E.D.), a Versus Arthritis Senior Research Fellowship Award (20875 to Q.-J.M.) and an MRC project grant (MR/K019392/1 to Q.-J.M.), a Grifols ‘ALTA’ Alpha-1-Antitrypsin Laurell’s Training Award and an Alpha-1-Foundation (grant number 614939) to J.E.C., and by a Wellcome Trust Sir Henry Dale Fellowship (208790/Z/17/Z to R.S.E.). N.M.R. is supported by a Medical Research Council Clinician Scientist Fellowship (MR/S022023/1). L.K.K. and V.J.P.-H. are recipients of EMBO Postdoctoral fellowships (ALTF 876-2021 and ALTF 577-2018, respectively). K.E.M. is supported by the Wellcome Trust through a Sir Henry Wellcome Postdoctoral Fellowship (220480/Z/20/Z). P.M.M. and J.B. were supported by Volkswagen ‘Life’ grant number 96827 and the DFG Excellence Cluster Physics of Life. We thank H. Andreas for frog maintenance; C. Godlee and M. Kaksonen for the gift of unpublished S. cerevisiae yeast strains and initial discussion of yeast experiments about temperature; P. Tran for S. pombe yeast strains; L. Miller for help with yeast work; A. Bertolotti for the kind gift of SH-SY5Y cells; and C. Russo, F. Jülicher, M. Gonzalez-Gaitan, K. Kruse, L. Blanchoin, J. Löwe, R. Hegde, P. Farrell and P. Crosby for discussion and suggestions; the staff at the companies Cherry Biotech and Elvesys, in particular T. Guérinier, for their help in designing and assembling the custom microfluidics system required for this project; the members of the Electronics and Mechanical workshops of the LMB for key support; the staff at the LMB Mass Spectrometry facility for performing and analysing MS data; and A. Prasad and T. Stevens for sharing the scripts for protein disorder and kinase motif predictions, respectively. Cartoons were created using BioRender. For the purpose of open access, the MRC Laboratory of Molecular Biology has applied a CC BY public copyright licence to any author accepted manuscript version arising.Optimum protein function and biochemical activity critically depends on water availability because solvent thermodynamics drive protein folding and macromolecular interactions1. Reciprocally, macromolecules restrict the movement of 'structured' water molecules within their hydration layers, reducing the available 'free' bulk solvent and therefore the total thermodynamic potential energy of water, or water potential. Here, within concentrated macromolecular solutions such as the cytosol, we found that modest changes in temperature greatly affect the water potential, and are counteracted by opposing changes in osmotic strength. This duality of temperature and osmotic strength enables simple manipulations of solvent thermodynamics to prevent cell death after extreme cold or heat shock. Physiologically, cells must sustain their activity against fluctuating temperature, pressure and osmotic strength, which impact water availability within seconds. Yet, established mechanisms of water homeostasis act over much slower timescales2,3; we therefore postulated the existence of a rapid compensatory response. We find that this function is performed by water potential-driven changes in macromolecular assembly, particularly biomolecular condensation of intrinsically disordered proteins. The formation and dissolution of biomolecular condensates liberates and captures free water, respectively, quickly counteracting thermal or osmotic perturbations of water potential, which is consequently robustly buffered in the cytoplasm. Our results indicate that biomolecular condensation constitutes an intrinsic biophysical feedback response that rapidly compensates for intracellular osmotic and thermal fluctuations. We suggest that preserving water availability within the concentrated cytosol is an overlooked evolutionary driver of protein (dis)order and function