Bidirectional Communication Between the Brain and Other Organs: The Role of Extracellular Vesicles

Abstract

A number of substances released by the brain under physiological and pathological conditions exert effects on other organs. In turn, substances produced primarily by organs such as bone marrow, adipose tissue, or the heart may have an impact on the metabolism and function and metabolism of the healthy and diseased brain. Despite a mounting amount of evidence supports such bidirectional communication between the brain and other organs, research on the function of molecular mediators carried by extracellular vesicles (EVs) is in the early stages. In addition to being able to target or reach practically any organ, EVs have the ability to cross the blood–brain barrier to transport a range of substances (lipids, peptides, proteins, and nucleic acids) to recipient cells, exerting biological effects. Here, we review the function of EVs in bidirectional communication between the brain and other organs. In a small number of cases, the role has been explicitly proven; yet, in most cases, it relies on indirect evidence from EVs in cell culture or animal models. There is a dearth of research currently available on the function of EVs-carrying mediators in the bidirectional communication between the brain and bone marrow, adipose tissue, liver, heart, lungs, and gut. Therefore, more studies are needed to determine how EVs facilitate communication between the brain and other organs.

Involvement of Astrocytes in the Formation, Maintenance, and Function of the Blood–Brain Barrier

“…Interestingly, in the brain, all the cell types are able to produce and release EVs (Figure 2) that, once received by other cells, can modify their activities and properties both under physiological and pathological conditions [49,[107][108][109][110].…”

“…Interestingly, in the brain, all the cell types are able to produce and release EVs (Figure 2) that, once received by other cells, can modify their activities and properties both under physiological and pathological conditions [49,[107][108][109][110]. On the other hand, all the brain cells are also able to catch materials delivered through the EVs under both physiological and pathological conditions [110][111][112][113][114][115][116][117][118][119].…”

Extracellular Vesicles: A Crucial Player in the Intestinal Microenvironment and Beyond

“…Subsequent research revealed the existence of four main types of microbiota vesicles: OMVs, produced by outer membrane budding; outer inner membrane vesicles (OIMVs) and explosive outer membrane vesicles (EOMVs), produced by explosive cell lysis; and cytoplasmic membrane vesicles (CMVs), produced by Gram-positive bacteria [ 103 ]. Unfortunately, the precise mechanisms of the release of certain microbiota vesicles remain unclear [ 104 ]. Bacteria-derived EVs generally encompass lipids, nucleic acids, proteins, and other small molecules.…”

Unraveling the Multifaceted Roles of Extracellular Vesicles: Insights into Biology, Pharmacology, and Pharmaceutical Applications for Drug Delivery

“…Although orally administered EVs were distributed to the liver, lung, spleen, ovary, colon, kidney, pancreas, and finally the brain four days after administration, IV-administered EVs accumulate mostly in the liver [ 481 ]. The ability of EVs to cross the BBB bidirectionally [ 385 , 523 ] makes EVs attractive as nano-biocarriers for drug delivery to the brain. Betzer et al, 2017 found that intranasal administration of the EVs resulted in a significant degree of enrichment of EVs in the brain [ 524 ].…”