Project description:The transcriptional potential of RIPK3 in a non-infectious system in neurons is unclear. Here we found that RIPK3 activation, independent of any upstream signals is sufficient to induce anti-viral transcription in neurons.
Project description:The full transcriptional RIPK3-dependent transcriptional potential in MEFs is unknown. Here, we found that RIPK3 is a dominant driver of anti-viral and inflammatory transcription in MEFs.
Project description:Here, we characterize RIPK3-dependent transcriptional responses in cortical neurons following infection with neurotropic flaviviruses. Neurons were infected with either Zika virus (ZIKV) strain MR766 at an MOI of 0.1, West Nile virus (WNV) strain TX 2002-HC at an MOI of 0.001, or a saline mock solution. Neurons were derived from mice lacking RIPK3 expression (Ripk3-/-) or wildtype controls. These studies revealed a number of antiviral genes whose upregulation following viral infection is absent in neurons lacking RIPK3, a subset of which were validated using qRT-PCR.
Project description:Necroptosis is a programmed lytic cell death involving active cytokine production and plasma membrane rupture through distinct signaling cascades. However, it remains challenging to delineate this inflammatory cell death pathway at specific signaling nodes with spatiotemporal accuracy. To address this challenge, we developed an optogenetic system, termed Light-activatable Receptor-Interacting Protein Kinase 3 or La-RIPK3, to enable ligand-free, optical induction of RIPK3 oligomerization. La-RIPK3 activation dissects RIPK3-centric lytic cell death through the induction of RIPK3-containing necrosome, which mediates cytokine production and plasma membrane rupture. Bulk RNA-Seq analysis reveals that RIPK3 oligomerization results in partially overlapped gene expression compared to pharmacological induction of necroptosis. However, La-RIPK3 activates a group of genes likely regulated by RIPK3 kinase-independent processes. Using patterned light stimulation delivered by a spatial light modulator, we demonstrate precise spatiotemporal control of necroptosis in La-RIPK3-transduced HT-29 cells. Optogenetic control of proinflammatory lytic cell death could lead to the development of innovative experimental strategies to finetune the immune landscape for disease intervention.
Project description:The full transcriptional RIPK3-dependent transcriptional potential is unknown. Here, we found that RIPK3 is a dominant driver of anti-viral transcription in neurons following Zika virus infection.
Project description:Astrocyte activation is a common feature of neurodegenerative diseases. However, the ways in which dying neurons influence the activity of astrocytes is poorly understood. RIPK3 signaling has recently been described as a key regulator of neuroinflammation, but whether this kinase mediates astrocytic responsiveness to neuronal death has not yet been studied. Here, we used the MPTP model of Parkinson’s disease to show that activation of astrocytic RIPK3 drives dopaminergic cell death and axon damage. Transcriptomic profiling revealed that astrocytic RIPK3 promoted gene expression associated with neuroinflammation and movement disorders, and this coincided with significant engagement of DAMP signaling. Using human cell culture systems, we show that factors released from dying neurons signal through RAGE to induce RIPK3-dependent astrocyte activation. These findings highlight a mechanism of neuron-glia crosstalk in which neuronal death perpetuates further neurodegeneration by engaging inflammatory astrocyte activation via RIPK3.
Project description:While recent work has identified roles for cytokines and inflammation in the regulation of neural activity, the capacity for cell intrinsic innate immune signaling within neurons to influence neurotransmission remains poorly understood. However, the existing evidence linking immune signaling with neuronal activity suggests that modulation of neurotransmission may serve previously undefined roles in host protection and pathogen control within the central nervous system. Here, we identify a specialized function for RIPK3, a kinase traditionally associated with necroptotic cell death, in preserving neuronal survival during neurotropic flavivirus infection through the suppression of excitatory neurotransmission. We show that RIPK3 coordinates transcriptomic changes in neurons that suppress neuronal glutamate signaling, thereby desensitizing neurons to excitotoxic cell death. These effects occur independently of the traditional functions of RIPK3 in promoting MLKL-dependent necroptosis and NFκB-mediated inflammatory transcription. Instead, RIPK3 promotes phosphorylation of the key neural regulatory kinase CAMKII, which in turn activates the transcription factor CREB to drive a neuroprotective transcriptional program and suppress deleterious glutamatergic signaling. These findings identify an unexpected function for a canonical cell death protein in promoting neuronal survival during viral infection through the modulation of neuronal activity, highlighting new mechanisms of neuroimmune crosstalk.
Project description:To examine the repertoires of genes expressed in individual fru P1-expressing neurons, we performed single cell sequencing. The analysis was performed on male and female central nervous system tissues (48-hour pupal stage), from flies that expressed membrane-bound GFP in fru P1 neurons. We chose this developmental stage to gain further insight into how genes direct development of fru P1 neurons, as this is the stage where FruM has peak expression (in ~2,000 neurons).