Cells Across the Tree of Life Exchange ‘Text Messages’ Using RNA

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"... There is one way RNA can survive outside a cell unscathed: in a tiny, protective bubble. For decades, researchers have noticed cells releasing these bubbles of cell membrane, called extracellular vesicles (EVs), packed with degraded RNA, proteins and other molecules. But these sacs were considered little more than trash bags that whisk broken-down molecular junk out of a cell during routine decluttering.

Then, in the early 2000s, experiments ... revealed that the RNA inside some EVs didn’t look like trash. The cocktail of RNA sequences was considerably different from those found inside the cell, and these sequences were intact and functional(opens a new tab). When Valadi’s team exposed human cells to EVs from mouse cells, they were shocked to observe the human cells take in the RNA messages and “read” them to create functional proteins they otherwise wouldn’t have been able to make. ...

In 2024, new studies have exposed additional layers of this story, showing, for example, that along with bacteria and eukaryotic cells, archaea also exchange(opens a new tab) vesicle-bound RNA, which confirms that the phenomenon is universal to all three domains of life. Another study has expanded our understanding of cross-kingdom cellular communication by showing that plants and infecting fungi can use packets of havoc-wreaking RNA(opens a new tab) as a form of coevolutionary information warfare: An enemy cell reads the RNA and builds self-harming proteins with its own molecular machinery. ..."

Cells Across the Tree of Life Exchange ‘Text Messages’ Using RNA | Quanta Magazine "Long known as a messenger within cells, RNA is increasingly seen as life’s molecular communication system — even between organisms widely separated by evolution."

Unique and parallel Flow of Information Identified in The Human Brain

Amazing stuff! How human brains maybe different from those of our closest relatives, i.e. apes!

"... A team led by researchers from the Swiss Federal Institute of Technology in Lausanne (EPFL) in Switzerland used advanced data analysis techniques on top of functional magnetic resonance imaging (fMRI) scans to analyze brain activity in humans, mice, and macaques.

Comparing the resulting brain 'traffic maps', the researchers found that the human brain uses multiple parallel pathways to shift information from one region to another, whereas the mice and macaque brains use just single channels. 
"What's new in our study is the use of multimodal data in a single model combining two branches of mathematics: graph theory, which describes the polysynaptic roadmaps; and information theory, which maps information transmission (or traffic) via the roads," ...

What's more, the researchers discovered that these parallel pathways are as unique as fingerprints: studying the particular way that information flows around a brain can distinguish individual nervous systems. ..."

"... To achieve this, the researchers used open-source diffusion (DWI) and functional magnetic resonance imaging (fMRI) data from humans, macaques, and mice, which was gathered while subjects were awake and at rest. The DWI scans allowed the scientists to reconstruct the brain “road maps”, and the fMRI scans allowed them to see different brain regions light up along each “road”, which indicated that these pathways were relaying neural information. ...
“Such parallel processing in human brains has been hypothesized, but never observed before at a whole-brain level,” ..."

From the abstract:

"Brain communication, defined as information transmission through white-matter connections, is at the foundation of the brain’s computational capacities that subtend almost all aspects of behavior: from sensory perception shared across mammalian species, to complex cognitive functions in humans. How did communication strategies in macroscale brain networks adapt across evolution to accomplish increasingly complex functions? By applying a graph- and information-theory approach to assess information-related pathways in male mouse, macaque and human brains, we show a brain communication gap between selective information transmission in non-human mammals, where brain regions share information through single polysynaptic pathways, and parallel information transmission in humans, where regions share information through multiple parallel pathways. In humans, parallel transmission acts as a major connector between unimodal and transmodal systems. The layout of information-related pathways is unique to individuals across different mammalian species, pointing at the individual-level specificity of information routing architecture. Our work provides evidence that different communication patterns are tied to the evolution of mammalian brain networks."

Unique Flow of Information Identified in The Human Brain : ScienceAlert

More parallel 'traffic' observed in human brains than in animals (Source: EPFL) In a study comparing human brain communication networks with those of macaques and mice, EPFL researchers found that only the human brains transmitted information via multiple parallel pathways, yielding new insights into mammalian evolution.

Evidence for increased parallel information transmission in human brain networks compared to macaques and male mice (open access)

In the mouse and macaque brains, information was sent along a single “road”, while in humans, there were multiple parallel pathways between the same source and target.

Research discovers new type of cellular communication in the brain

Amazing stuff!

"Scientists ... have discovered hundreds of proteins that are constantly transported throughout the healthy brain in small membrane-enclosed sacs, revealing a new form of communication between brain cells. ...

The proteins identified included many with known functions in the brain, including the tau and synuclein seen moving between cells in Alzheimer’s disease.

“This is a confirmation that in the healthy brain, tau and synuclein—and their movement around the brain—is normal,” ... “But with Alzheimer’s disease it’s a toxic form of the protein that is transported between neurons.” ..."

From the abstract:

"Intercellular transfer of toxic proteins between neurons is thought to contribute to neurodegenerative disease, but whether direct interneuronal protein transfer occurs in the healthy brain is not clear. To assess the prevalence and identity of transferred proteins and the cellular specificity of transfer, we biotinylated retinal ganglion cell proteins in vivo and examined biotinylated proteins transported through the rodent visual circuit using microscopy, biochemistry, and mass spectrometry. Electron microscopy demonstrated preferential transfer of biotinylated proteins from retinogeniculate inputs to excitatory lateral geniculate nucleus (LGN) neurons compared with GABAergic neurons. An unbiased mass spectrometry-based screen identified ∼200 transneuronally transported proteins (TNTPs) isolated from the visual cortex. The majority of TNTPs are present in neuronal exosomes, and virally expressed TNTPs, including tau and β-synuclein, were detected in isolated exosomes and postsynaptic neurons. Our data demonstrate transfer of diverse endogenous proteins between neurons in the healthy intact brain and suggest that TNTP transport may be mediated by exosomes."

Scripps Research discovers new type of cellular communication in the brain | Scripps Research The finding can reveal how protein transport goes awry in conditions including Alzheimer’s and autism.

Proteomic screen reveals diverse protein transport between connected neurons in the visual system (open access)