Deficiency of the ywhaz gene, involved in neurodevelopmental disorders, alters brain activity and behaviour in zebrafish

Genetic variants in YWHAZ contribute to psychiatric disorders such as autism spectrum disorder and schizophrenia, and have been related to an impaired neurodevelopment in humans and mice. Here, we have used zebrafish to investigate the mechanisms by which YWHAZ contributes to neurodevelopmental disorders. We observed that ywhaz expression was pan-neuronal during developmental stages and restricted to Purkinje cells in the adult cerebellum, cells that are described to be reduced in number and size in autistic patients. We then performed whole-brain imaging in wild-type and ywhaz CRISPR/Cas9 knockout (KO) larvae and found altered neuronal activity and connectivity in the hindbrain. Adult ywhaz KO fish display decreased levels of monoamines in the hindbrain and freeze when exposed to novel stimuli, a phenotype that can be reversed with drugs that target monoamine neurotransmission. These findings suggest an important role for ywhaz in establishing neuronal connectivity during development and modulating both neurotransmission and behaviour in adults

Iron accumulation drives fibrosis, senescence and the senescence-associated secretory phenotype.

Fibrogenesis is part of a normal protective response to tissue injury that can become irreversible and progressive, leading to fatal diseases. Senescent cells are a main driver of fibrotic diseases through their secretome, known as senescence-associated secretory phenotype (SASP). Here, we report that cellular senescence, and multiple types of fibrotic diseases in mice and humans are characterized by the accumulation of iron. We show that vascular and hemolytic injuries are efficient in triggering iron accumulation, which in turn can cause senescence and promote fibrosis. Notably, we find that senescent cells persistently accumulate iron, even when the surge of extracellular iron has subdued. Indeed, under normal conditions of extracellular iron, cells exposed to different types of senescence-inducing insults accumulate abundant ferritin-bound iron, mostly within lysosomes, and present high levels of labile iron, which fuels the generation of reactive oxygen species and the SASP. Finally, we demonstrate that detection of iron by magnetic resonance imaging might allow non-invasive assessment of fibrotic burden in the kidneys of mice and in patients with renal fibrosis. Our findings suggest that iron accumulation plays a central role in senescence and fibrosis, even when the initiating events may be independent of iron, and identify iron metabolism as a potential therapeutic target for senescence-associated diseases.Acknowledgements: We are grateful to K. Raj (Altos Laboratories) for his help with the experiments on replicative senescence. We thank D. Muñoz Espin (University of Cambridge) for sending us the IMR90 cells stably transduced with tamoxifen inducible Ras-G12V. We thank R. Mendez (IRB) for the H5V and HUVEC cells. We thank staf at the TEM-SEM Electron Microscopy Unit from Scientific and Technological Centers (CCiTUB), Universitat de Barcelona for their support and advice on TEM techniques. We are thankful to the Magnetic Resonance Imaging Core Facility of the Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) for the scientific and technical support in MRI acquisition and analysis. M.M. received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement (no. 794744) and from the Spanish Ministry of Science and Innovation (MCIN) (RYC2020-030652-I/AEI/10.13039/501100011033). V.L.P. was a recipient of a predoctoral contract from the Spanish Ministry of Education (FPU-18/05917). K.M. was a recipient of fellowships from the German Cardiac, the German Research Foundation and a postdoctoral contract Juan de la Cierva from the MCIN. F.H.G. was supported by the PhD4MD Collaborative Research Training Program for Medical Doctors (IRB Barcelona/Hospital Clinic/IDIBAPS). M. Sanchez was funded by grants PID2021- 122436OB-I00 from MCIN/AEI/10.13039/501100011033/FEDER, UE, RETOS COLABORACION RTC2019-007074-1 from MCIN/ AEI/10.13039/501100011033. C.L.-M. was a recipient of a predoctoral contract from the Spanish Ministry of Education (FPU-18/02965). G.A. was funded by the Instituto de Salud Carlos III through project PI 20/01360, FEDER funds. J.M.C. was funded by the Instituto de Salud Carlos III through projects PI18/00910 and PI21/00931 (co-funded by European Regional Development Fund, a way to build Europe) and thanks the CERCA Programme/ Generalitat de Catalunya for institutional support. Work in the laboratory of M. Serrano was funded by the IRB and ‘laCaixa’ Foundation and by grants from the Spanish Ministry of Science co-funded by the European Regional Development Fund (SAF2017- 82613-R), European Research Council (ERC-2014-AdG/669622) and grant RETOS COLABORACION RTC2019-007125-1 from MCIN/AEI and Secretaria d’Universitats i Recerca del Departament d’Empresa i Coneixement of Catalonia (Grup de Recerca consolidat 2017 SGR 282

Deficiency of the ywhaz gene, involved in neurodevelopmental disorders, alters brain activity and behaviour in zebrafish

Genetic variants in YWHAZ contribute to psychiatric disorders such as autism spectrum disorder and schizophrenia, and have been related to an impaired neurodevelopment in humans and mice. Here, we have used zebrafish to investigate the mechanisms by which YWHAZ contributes to neurodevelopmental disorders. We observed that ywhaz expression was pan-neuronal during developmental stages and restricted to Purkinje cells in the adult cerebellum, cells that are described to be reduced in number and size in autistic patients. We then performed whole-brain imaging in wild-type and ywhaz CRISPR/Cas9 knockout (KO) larvae and found altered neuronal activity and connectivity in the hindbrain. Adult ywhaz KO fish display decreased levels of monoamines in the hindbrain and freeze when exposed to novel stimuli, a phenotype that can be reversed with drugs that target monoamine neurotransmission. These findings suggest an important role for ywhaz in establishing neuronal connectivity during development and modulating both neurotransmission and behaviour in adults