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Gokhale, R.

Publications and source records attributed to Gokhale, R..

6 recordsLinked to original sources

Weaning imprints a hybrid cytotoxic-regulatory identity on intestinal CD4+ T lymphocytes

The intestinal immune system must adapt as the neonatal gut shifts from milk to solid food and becomes densely colonized. How the T cell compartment is established under these conditions remains unclear. Using fate-mapping to timestamp naive T cells, with imaging, transcriptomic, and repertoire analyses, we tracked them from suckling to adulthood. Intestinal T cell entry peaked at weaning, coinciding with relocation from crypts to villi guided by the tissue microenvironment and, partly, the microbiota. T cells timestamped at suckling persisted into adulthood and, at weaning, adopted a transient cytotoxic-regulatory state in the lamina propria, with granzyme B expression microbiota-dependent only in the ileum. Clonal expansions at weaning were restricted to the small intestinal lamina propria and absent in germ-free mice. Most expanded clones recognized early-life commensals. Weaning is a physiological window of transient inflammation imprinting a hybrid CD4 T cell compartment, suggesting that early-life commensals modulate T cell selection.

immunology↗

Distributed disruption and remodelling of synaptome architecture following traumatic brain injury

A single cortical impact in mice altered the number and molecular composition of excitatory synapses across 222 brain regions. Early effects targeted synapses with rapid protein turnover, followed by changes in slow-turnover synapses. This injury-induced remodelling of synaptome architecture mirrors responses to genetic mutation, ageing, sleep deprivation and experience, suggesting that reorganisation of excitatory synapse populations is a shared mechanism underlying brain plasticity across diverse conditions.

neuroscience↗

Sleep maintains excitatory synapse diversity in the cortex and hippocampus

How sleep deprivation affects cognition remains elusive. Synaptome mapping of excitatory synapses in 125 regions of the mouse brain revealed that sleep deprivation selectively reduces synapse diversity in the cortex and hippocampus. Sleep deprivation targeted specific types and subtypes of excitatory synapses while maintaining total synapse density. Altered synaptic responses to neural oscillations in a computational model suggest that sleep prevents cognitive impairments by maintaining normal brain synaptome architecture.

neuroscience↗

Developmental resilience of synaptome architecture

Neurodevelopmental disorders of genetic origin delay the acquisition of normal abilities and cause disabling phenotypes. Spontaneous attenuation and even complete amelioration of symptoms in early childhood and adolescence occur in many disorders1-10, suggesting that brain circuits possess an intrinsic capacity to repair themselves. We examined the molecular composition of almost a trillion excitatory synapses on a brain-wide scale between birth and adulthood in mice carrying a mutation in the homeobox transcription factor Pax6, a neurodevelopmental disorder model11. Pax6 haploinsufficiency had no impact on total synapse number at any age. By contrast, the postnatal expansion of synapse diversity and acquisition of normal synaptome architecture were delayed in all brain regions, interfering with network and cognitive functions. Specific excitatory synapse types and subtypes were affected in two key developmental age-windows. These phenotypes were reversed within 2-3 weeks of onset, restoring synaptome architecture to its normal developmental trajectory. Synapse subtypes with high rates of protein turnover mediated these events. These results show synaptome remodelling confers resilience to neurodevelopmental disorders.

neuroscience↗

A brain atlas of synapse protein lifetime across the mouse lifespan.

Protein turnover is required for synapse maintenance and remodelling and may impact memory duration. We quantified the lifetime of postsynaptic protein PSD95 in individual excitatory synapses across the mouse brain and lifespan, generating the Protein Lifetime Synaptome Atlas. Excitatory synapses have a wide range of protein lifetimes that may extend from a few hours to several months, with distinct spatial distributions in dendrites, neuron types and brain regions. Short protein lifetime (SPL) synapses are enriched in developing animals and in regions controlling innate behaviors, whereas long protein lifetime (LPL) synapses accumulate during development, are enriched in the cortex and CA1 where memories are stored, and are preferentially preserved in old age. The protein lifetime synaptome architecture is disrupted in an autism model, with synapse protein lifetime increased throughout the brain. These findings add a further layer to synapse diversity in the brain and enrich prevailing concepts in behavior, development, ageing and brain repair.

neuroscience↗

A lifespan program of mouse synaptome architecture

How synapses change molecularly during the lifespan and across all brain circuits is unknown. We analyzed the protein composition of billions of individual synapses from birth to old age on a brain-wide scale in the mouse, revealing a program of changes in the lifespan synaptome architecture spanning individual dendrites to the systems level. Three major phases were uncovered, corresponding to human childhood, adulthood and old age. An arching trajectory of synaptome architecture drives the differentiation and specialization of brain regions to a peak in young adults before dedifferentiation returns the brain to a juvenile state. This trajectory underscores changing network organization and hippocampal physiology that may account for lifespan transitions in intellectual ability and memory, and the onset of behavioral disorders. One sentence summaryThe synaptome architecture of the mouse brain undergoes continuous changes that organize brain circuitry across the lifespan.

neuroscience↗