Membrane potential mediates the cellular response to mechanical pressure
Mechanical forces influence cellular decisions to grow, die, or differentiate, through largely mysterious mechanisms. Separately, changes in resting membrane potential have been observed in development, differentiation, regeneration, and cancer. We demonstrate that membrane potential is an important mediator of cellular response to mechanical pressure. We show that mechanical forces acting on the cell change cellular biomass density, which, in turn, alters membrane potential. Membrane potential then regulates cell number density in epithelia by controlling cell growth, proliferation, and cell elimination. Mechanistically, we show that changes in membrane potential control signaling through the Hippo and mitogen-activated protein kinase (MAPK) pathways and potentially other signaling pathways that originate at the cell membrane. While many molecular interactions are known to affect Hippo signaling, the upstream signal that activates the canonical Hippo pathway at the membrane has previously been elusive. Our results establish membrane potential as an important regulator of growth and tissue homeostasis.
Autoantibody-triggered podocyte membrane budding drives autoimmune kidney disease
Chronic kidney disease affects 1 in 10 people worldwide, with damage to specialized blood filter cells of the kidney, called podocytes, playing a critical role. In membranous nephropathy (MN), a major cause of nephrotic syndrome, circulating autoantibodies attack proteins on podocyte foot processes (FPs), damaging the kidney's filtration barrier. Our study shows that these autoantibodies trigger the formation of antigen-autoantibody aggregates on the podocyte FP plasma membrane. These aggregates bud off as stalked vesicles, termed autoimmunoglobulin-triggered extracellular vesicles (AIT-EVs), which are released into the urine. AIT-EVs carry disease-causing autoantibodies, their target antigens, essential FP proteins, and disease-associated stressors representing a mechanism for removing immune complexes (ICs) and waste. However, their excessive release leads to FP effacement and podocyte dysfunction. In MN patients, urinary AIT-EVs correspond to glomerular urinary-space aggregates. Enriching AIT-EVs enables detection and monitoring of pathogenic autoantibodies, suggesting a non-invasive approach for autoimmune kidney disease diagnosis and therapy.
A stepwise decoding mechanism for heat sensing in plants connects lipid remodeling to a nuclear signaling cascade
Heat stress triggers cell membrane lipid remodeling, yet whether this signals plants to perceive high temperatures and how such physical signals are decoded into biological signals remains unclear. Here, we demonstrate that diacylglycerol kinase 7 (DGK7) responds to heat stress at the plasma membrane, converting diacylglycerol into the second messenger, phosphatidic acid (PA). Subsequently, metal-dependent phosphodiesterase (MdPDE1) senses PA, acquires its activity by binding to PA, and translocates to the nucleus to degrade another second messenger, cyclic adenosine monophosphate (cAMP). MdPDE1 then elicits transcriptional landscape changes via altering cAMP signaling. Furthermore, G protein subunit thermotolerance 2 (TT2) inhibits DGK7 activity by Ser dephosphorylation, blocking MdPDE1 activity and nuclear translocation. Notably, field trials demonstrated the promising applications of this mechanism that confers varying degrees of rice thermotolerance as needed. This study establishes a complete hierarchical thermo-decoding mechanism that opens opportunities for creating customized heat-tolerant crops, aiding in mitigating yield losses from global warming.
pTα enhances mRNA translation and potentiates CAR T cells for solid tumor eradication
Current chimeric antigen receptor (CAR) therapies are effective against a range of hematological malignancies and autoimmune disorders but have shown limited activity against solid tumors. In searching for effective means to enhance the functional persistence and potency of CAR T cells, we explored the potential of integrating pre-T cell features into canonical CD28-based CARs. Thymocytes undergo a proliferation burst during the β-selection developmental stage, which is driven by the pre-T cell receptor and its unique pTα chain. CARs harboring the pTα 1A domain imparted greater expansion, cytokine production, and in vivo persistence to T cells, accompanied by lowered exhaustion and greater long-term tumor control in multiple liquid and solid tumor models. CARs incorporating the 1A domain showed sustained phosphorylation of the mRNA translation master regulator Y-Box Binding Protein 1 (YBX1), which was required for enhanced tumor eradication. The programming of mRNA translation in T cells opens another avenue for regulating and potentiating immunotherapy.
Fertilization triggers early proteomic symmetry breaking in mammalian embryos
While non-mammalian embryos often rely on spatial pre-patterning, mammalian development has long been thought to begin with equivalent blastomeres. However, emerging evidence challenges this. Here, using multiplexed and label-free single-cell proteomics, we identify over 300 asymmetrically abundant proteins-many involved in protein degradation and transport-dividing mouse 2-cell-stage blastomeres into two distinct clusters, which we term alpha and beta. These proteomic asymmetries are detectable as early as the zygote stage, intensify by the 4-cell stage, and correlate with the sperm entry site, implicating fertilization as a symmetry-breaking event. Splitting 2-cell-stage embryos into halves reveals that beta blastomeres possess greater developmental potential than alpha blastomeres. Similar clustering and protein enrichment patterns found in human 2-cell embryos suggest this early asymmetry might be conserved. These findings uncover a previously unrecognized proteomic pre-patterning triggered by fertilization in mammalian embryos, with important implications for understanding totipotency and early lineage bias.
The unique architecture of umbrella toxins permits a two-tiered molecular bet-hedging strategy for interbacterial antagonism
Bacteria exist in competitive and rapidly changing environments in which the nature of future threats cannot be easily predicted. Streptomyces coelicolor produces three antibacterial umbrella particles that harbor distinct polymorphic toxin domains and an overlapping set of six diversified lectins. Here, we show that the exquisite specificity of umbrella particles derives from lectin-mediated species-specific binding to previously undescribed hypervariable surface glycoconjugates. A cryo-electron microscopy (cryo-EM) structure of one such lectin in complex with its oligosaccharide substrate defines the molecular basis for targeting through the coordinated recognition of multiple glycan features. Biochemical and genetic studies of several target species, in conjunction with lectin-swapping experiments, support a model whereby S. coelicolor umbrella toxin diversification at the levels of lectin composition and toxin polymorphism represents a unique, two-tiered bet-hedging strategy. Bioinformatic analyses support this as a means by which the unusual architecture of umbrella toxins offers Streptomyces a generalizable strategy to antagonize an unpredictable array of competitors.
Retraction notice to: Transcriptome-scale RNA-targeting CRISPR screens reveal essential lncRNAs in human cells
Renal PIEZO2 is an essential regulator of renin
Renin synthesis and release is the rate-limiting step of the renin-angiotensin-aldosterone system (RAAS) that controls fluid homeostasis. A major activator of the RAAS is a decrease in perfusion pressure within the kidneys, suggesting a link between renal mechanotransduction and renin. However, the identity of the mechanosensor(s) in the kidneys and their physiological significance to the RAAS remain unclear. We find that loss of the force-gated nonselective cation channel PIEZO2 in cells of renin lineage dysregulates the RAAS by elevating renin. We observe that PIEZO2 is expressed in renin-producing juxtaglomerular granular cells and is required for their calcium dynamics in vivo. PIEZO2 deficiency in cells of renin lineage drives renin-dependent and MAS-receptor-dependent glomerular hyperfiltration and regulates the RAAS during acute and chronic blood volume challenges. Collectively, our study identifies PIEZO2 as an essential regulator of juxtaglomerular granular cell calcium activity and renin in vivo.
A fin-loop-like structure in GPX4 underlies neuroprotection from ferroptosis
Ferroptosis, driven by uncontrolled peroxidation of membrane phospholipids, is distinct from other cell death modalities because it lacks an initiating signal and is surveilled by endogenous antioxidant defenses. Glutathione peroxidase 4 (GPX4) is the guardian of ferroptosis, although its membrane-protective function remains poorly understood. Here, structural and functional analyses of a missense mutation in GPX4 (p.R152H), which causes early-onset neurodegeneration, revealed that this variant disrupts membrane anchoring without considerably impairing its catalytic activity. Spatiotemporal Gpx4 deletion or neuron-specific GPX4 expression in mice induced degeneration of cortical and cerebellar neurons, accompanied by progressive neuroinflammation. Patient induced pluripotent stem cell (iPSC)-derived cortical neurons and forebrain organoids displayed increased ferroptotic vulnerability, mirroring key pathological features, and were sensitive to ferroptosis inhibition. Neuroproteomics revealed Alzheimer's-like signatures in affected brains. These findings highlight the necessity of proper GPX4 membrane anchoring, establish ferroptosis as a key driver of neurodegeneration, and provide the rationale for targeting ferroptosis as a therapeutic strategy in neurodegenerative disease.
An archaeal transcription factor bridges prokaryotic and eukaryotic regulatory paradigms
Archaeal transcription is a hybrid of eukaryotic and prokaryotic features: an RNA polymerase II (RNAPII)-like polymerase transcribes genes organized in circular chromosomes within cells devoid of a nucleus. Consequently, archaeal genomes are depleted of transcriptional regulators found in other domains of life. Here, we outline the discovery of a cryptic, archaea-specific family of ligand-binding regulatory transcription factors (TFs), called AmzR (archaeal metabolite-sensing zipper-like regulators). We identify AmzR using an evolution-based genetic screen and show that it is a repressor of methanogenic growth on methylamines in the archaeon Methanosarcina acetivorans. AmzR binds its target promoters as an oligomer using paired basic α-helices akin to eukaryotic leucine zippers. AmzR also binds methylamines, which reduces its DNA-binding affinity and allows it to function as a one-component system commonly found in prokaryotes, while containing a eukaryotic-like DNA-binding motif. The AmzR family of TFs are widespread in archaea and broaden the scope of innovations at the prokaryote-eukaryote interface.
The effect of shingles vaccination at different stages of the dementia disease course
Using natural experiments, we have previously reported that live-attenuated herpes zoster (HZ) vaccination appears to have prevented or delayed dementia diagnoses in both Wales and Australia. Here, we find that HZ vaccination also reduces mild cognitive impairment diagnoses and, among patients living with dementia, deaths due to dementia. Exploratory analyses suggest that the effects are not driven by a specific dementia type. Our approach takes advantage of the fact that individuals who had their eightieth birthday just after the start date of the HZ vaccination program in Wales were eligible for the vaccine for 1 year, whereas those who had their eightieth birthday just before were ineligible and remained ineligible for life. The key strength of our natural experiments is that these comparison groups should be similar in all characteristics except for a minute difference in age. Our findings suggest that live-attenuated HZ vaccination prevents or delays mild cognitive impairment and dementia and slows the disease course among those already living with dementia.
Psilocybin triggers an activity-dependent rewiring of large-scale cortical networks
Psilocybin holds promise as a treatment for mental illnesses. One dose of psilocybin induces structural remodeling of dendritic spines in the medial frontal cortex in mice. The dendritic spines would be innervated by presynaptic neurons, but the sources of these inputs have not been identified. Here, using monosynaptic rabies tracing, we map the brain-wide distribution of inputs to frontal cortical pyramidal neurons. We discover that psilocybin's effect on connectivity is network specific, strengthening the routing of inputs from perceptual and medial regions (homolog of the default mode network) to subcortical targets while weakening inputs that are part of cortico-cortical recurrent loops. The pattern of synaptic reorganization depends on the drug-evoked spiking activity because silencing a presynaptic region during psilocybin administration disrupts the rewiring. Collectively, the results reveal the impact of psilocybin on the connectivity of large-scale cortical networks and demonstrate neural activity modulation as an approach to sculpt the psychedelic-evoked neural plasticity.
IL-1R1-positive dorsal raphe neurons drive self-imposed social withdrawal in sickness
Sick animals exhibit behavioral changes that extend beyond physiological symptoms, such as appetite loss and hypoactivity, and include a decline in social interactions. While social isolation during sickness has been recognized to have the evolutionary benefit of staving off disease spread, the molecular and neural mechanisms underlying this response remain unclear. Cytokines-immune-derived signaling molecules-have emerged as neuromodulators impacting brain function during inflammation. Through behavioral screening, we identify a unique role for the cytokine interleukin-1β (IL-1β) in promoting social withdrawal during sickness. IL-1β directly modulates the activity of IL-1R1-expressing neurons in the dorsal raphe nucleus (DRN) (IL-1R1). Activation of these neurons is sufficient to elicit social withdrawal, while their inhibition or genetic deletion of IL-1R1 rescues self-imposed social isolation during systemic inflammation. Our findings reveal a neural mechanism that actively promotes social disengagement in sick animals, highlighting the role of IL-1R1 neurons in driving these behavioral adaptations.
Properties and functions of transcriptionally distinct enteric neurons
The influence of the nervous system on the intestine is carried out by a combination of enteric, sensory, and autonomic innervation. However, disambiguating the functions of these physiologically distinct intestine-innervating neuronal populations has been a challenge. Here, we develop a collection of mouse genetic tools that enable precise manipulation and examination of intestine-innervating neurons, particularly those in the enteric nervous system, which represent the most frequent of the intestine-innervation neural populations. We report that an array of transcriptionally distinct enteric neuron subpopulations has distinct morphological specializations and influences on intestinal function, including controlling fecal output, fecal hydration, and food intake. We also report that subpopulations within the enteric nervous system require extrinsic innervation to exert control over intestinal transit or food intake. Collectively, these genetic approaches enable interrogation of the enteric nervous system and further study of its interactions with broader neural networks in the body.
Turning up the volume: BNST couples internal state to consumption
In this issue of Cell, Canovas and colleagues identify a consummatory dial in the brain that controls ingestion levels in a state-dependent manner. By continuing to trace the flow of sweet taste information, the authors identify a generalized intensity dial that broadly modulates consumption.
Activation-induced cytidine deaminase: The missing piece of many puzzles
Twenty-five years ago, two Cell papers reported the key missing functional piece in three molecular puzzles. The genetic swapping of immunoglobulin constant regions, the mutational fine-tuning of antibody specificity, and a baffling human immunodeficiency were traced to the action of one enzyme: activation-induced cytidine deaminase (AID).
A systematic approach to tuberculosis vaccine development
M. tuberculosis is once again the leading infectious cause of death worldwide despite the existence of a licensed vaccine (BCG). In this issue of Cell, Vidal et al. systematically evaluate 42 candidate antigens and develop a trivalent mRNA vaccine that demonstrates effective and durable protection from tuberculosis in several mouse models. This vaccine also enhances protection conferred by BCG.
Feeding from the sun-Successes and prospects in bioengineering photosynthesis for food security
There is an urgent need for increased crop productivity to reduce food insecurity and improve sustainability. Photosynthesis converts sunlight energy into carbohydrates, providing the source of nearly all of humanity's food. Photosynthesis is a key target for improvement, owing to inherent inefficiencies in the biochemical process. Over the last decade of advancements in bioengineering, strategies to increase the efficiency of photosynthesis were tested with proven enhancements to crop yields in field trials. Simple strategies like increasing the content of photosynthetic proteins have reliably increased photosynthesis and productivity in crops, as have more complex strategies such as bypassing photorespiration. While insertion of carbon-concentrating mechanisms into C plants remains an engineering challenge, modeling suggests that achieving that would have the greatest gain for crop improvement. This review discusses the many successes in improving photosynthesis achieved over the past decade and quantifies the potential for future engineering targets to increase crop productivity.
Thermodynamic principles link in vitro transcription factor affinities to single-molecule chromatin states in cells
The molecular details governing transcription factor (TF) binding and the formation of accessible chromatin are not yet quantitatively understood-including how sequence context modulates affinity, how TFs search DNA, the kinetics of TF occupancy, and how motif grammars coordinate binding. To resolve these questions for a human TF, erythroid Krüppel-like factor (eKLF/KLF1), we quantitatively compare, in high throughput, in vitro TF binding rates and affinities with in vivo single-molecule TF and nucleosome occupancies and in vivo-derived deep learning models. We find that 40-fold flanking sequence effects on affinity are consistent with distal flanks tuning TF search parameters and captured by a linear energy model. Motif recognition probability, rather than time in the bound state, drives affinity changes, and in vitro and in nuclei measurements exhibit consistent, minutes-long TF residence times. Finally, in vitro biophysical parameters predict in vivo sequence preferences and single-molecule chromatin states for unseen motif grammars.
Stress-induced sympathetic hyperactivation drives hair follicle necrosis to trigger autoimmunity
Stress has profound effects on health, yet how it damages tissues remains poorly understood. Here, we show that acute stress triggers rapid hair loss and initiates autoimmunity. Under stress, hyperactivated sympathetic nerves release excessive norepinephrine, causing necrosis in rapidly dividing hair follicle transit-amplifying cells (HF-TACs) while sparing most hair follicle stem cells (HFSCs). This differential sensitivity stems from differences in cell death pathways, metabolic strategies, and calcium homeostasis, which render HF-TACs more susceptible to norepinephrine-induced calcium surges. HF-TAC necrosis releases cellular debris that triggers macrophage-mediated clearance and dendritic cell activation, ultimately leading to the activation and amplification of autoreactive T cells that can attack the hair follicle under inflammatory insults. Our findings reveal mechanistically how stress causes immediate tissue damage in highly proliferative HF-TACs via sympathetic nerve-induced necrosis, which in turn fuels the activation of autoreactive T cells capable of mounting future attacks against the same tissue.
Innate immune and metabolic signals induce mitochondria-dependent membrane lysis via mitoxyperiosis
The combination of innate immune activation and metabolic disruption plays critical roles in many diseases, often leading to mitochondrial dysfunction and oxidative stress that drive pathogenesis. However, mechanistic regulation under these conditions remains poorly defined. Here, we report a distinct lytic cell death mechanism induced by innate immune signaling and metabolic disruption, independent of caspase activity and previously described pyroptosis, PANoptosis, necroptosis, ferroptosis, and oxeiptosis. Instead, mitochondria undergoing BAX/BAK1/BID-dependent oxidative stress maintained prolonged plasma membrane contact, leading to local oxidative damage, a process we termed mitoxyperiosis. This process then caused membrane lysis and cell death, termed mitoxyperilysis. mTORC2 regulated the cell death, and mTOR inhibition restored cytoskeletal activity for lamellipodia to retract and mobilize mitochondria away from the membrane, preserving integrity. Activating this pathway in vivo regressed tumors in an mTORC2-dependent manner. Overall, our results identify a lytic cell death modality in response to the synergism of innate immune signaling and metabolic disruption.
